
@article{lachlan_1998,
	title = {Who follows whom? {S}hoaling preferences and social learning of foraging information in guppies},
	volume = {56},
	doi = {http://dx.doi.org/10.1006/anbe.1998.0760},
	abstract = {Preferences of fish for different types of shoals may influence the transmission of novel information through them. We investigated the factors influencing the preferences of {guppies,Poecilia} reticulata, for different shoals in order to shed some light on how information transmission occurs. Adult subjects were given a choice between swimming with two diverging shoals of conspecifics that differed with respect to key characteristics. In six choice experiments, subjects discriminated between shoal partners on the basis of: (1) shoal size, subjects preferring a shoal of 10 to a single fish; (2) size of shoaling fish, small fish preferring small conspecifics rather than an equal number of large fish, while large fish showed no preference; (3) local foraging experience of shoaling fish, shoals containing fish that had previously been repeatedly fed in the experimental tank being preferred to shoals with no such experience; and (4) familiarity of shoaling fish, guppies preferring familiar rather than unfamiliar conspecifics. No discrimination on the basis of colour or hunger was observed. In addition, following a shoal to a food site on just three trials allowed guppies to learn a route, or food site, preference. Guppies were considerably more likely to learn to adopt the behaviour shown by members of a shoal of several demonstrators than an alternative behaviour shown by a single conspecific demonstrator. The relationship between preferences for different shoals and the social transmission of information is discussed in the light of these findings. The results suggest that shoaling preferences may strongly influence the social transmission of novel foraging information or feeding preferences through fish populations, and imply that learned infor-mation may diffuse through fish populations in a nonrandom, or directed, manner.},
	journal = {Animal Behaviour},
	author = {Robert F. Lachlan and Lucy Crooks and Kevin N. Laland},
	year = {1998},
	number = {1},
	pages = {181--190}
},

@article{bautista_2001,
	title = {To walk or to fly? {H}ow birds choose among foraging modes},
	volume = {98},
	abstract = {We test the predictive value of the main energetic currencies used in foraging theory using starlings that choose between two foraging modes (walking versus flying). Walking is low-cost, low-yield, whereas flying is the opposite. We fixed experimentally, at 11 different values, the amount of flight required to get one food reward, and for each flight cost value, we titrated the amount of walking until the birds showed indifference between foraging modes. We then compared the indifference points to those predicted by gross rate of gain over time, net rate of gain over time, and the ratio of gain to expenditure (efficiency). The results for the choice between modes show strong qualitative and quantitative support for net rate of gain over time over the alternatives. However, the birds foraged for only a fraction of the available time, indicating that the choice between foraging and resting could not be explained by any of these currencies. We suggest that this discrepancy could be accounted for functionally because nonenergetic factors such as predation risk may differ between resting and foraging in any mode but may not differ much between foraging modes, hence releasing the choice between foraging modes from the influence of such factors. Alternatively, the discrepancy may be attributable to the use of predictable (rather than stochastic) ratios of effort per prey in our experiment, and it may thus be better understood with mechanistic rather than functional arguments.},
	journal = {Proceedings of the National Academy of Sciences {(USA)}},
	author = {L M Bautista and J Tinbergen and A Kacelnik},
	year = {2001},
	number = {3},
	pages = {1089--1094},
},

@article{agrillo_2007a,
	title = {Discrimination of the larger shoal in the poeciliid fish \emph{{G}irardinus falcatus}},
	volume = {19},
	doi = {10.1080/08927014.2007.9522574},
	abstract = {Two decades of comparative studies have shown that numerical abilities are widespread in the animal kingdom. In particular, the ability to select the larger of two quantities (known as the ability to go for “more”) has been found in apes, dolphins, birds and amphibians. This primary quantity discrimination has not been investigated in fish in a systematic way although several studies suggest that fish have the ability to distinguish among different-sized groups of conspecifics. We investigated the spontaneous choice for the larger of two shoals in female goldbelly topminnows {({\textless}i{\textgreater}Girardinus} falcatus{\textless}/i{\textgreater}) and compared two different methods to determine an efficient procedure for studying the numerical competence of fish.
{\textless}br /{\textgreater}{\textless}br {/{\textgreater}Female} topminnows that were placed in a novel and potentially dangerous environment were found to choose the larger shoal suggesting that the capacity to go for “more” was similar to that observed in other non-verbal animals. The two methods proved not to be sensitive in revealing differences between the numerical contrasts, however, combining the results of the two experiments, we found that when groups differed in size by one individual, choice of the larger shoal was significantly above that predicted by chance up to a maximum of three fish in the larger shoal (i.e. 2 vs 1 and 3 vs 2 but not 4 vs 3 or larger). When presented with two shoals with a 1:2 numerical ratio, choice was significantly above chance in 4 vs 2 but not in 8 vs 4 comparisons.},
	number = {2},
	journal = {Ethology, Ecology and Evolution},
	author = {C. Agrillo and M. Dadda},
	year = {2007},
	pages = {145--157}
},

@article{abrahams_1989,
	title = {A determination of the energetic equivalence of the risk of predation},
	volume = {70},
	issn = {00129658},
	abstract = {The influence of predation risk on patch choice was measured by examining the spatial distribution of 10 guppies {(Poecilia} reticulata) between two feeders, at one of which there was a risk of predation. The distribution was assumed to be ideal free. Nine unique situations were examined using all possible combinations of three risk levels and three diet levels, for each sex of guppy separately. Both sex and diet level influenced the effect of predation risk on patch choice. For the females the effect of risk was highest at the intermediate diet level. However, the males exhibited the opposite response: the effect of risk of predation was lowest at the intermediate diet level. A simple equation was then used to predict how much extra food (representing the energetic equivalent of risk) must be added to the risky patch for the guppies to become indifferent to the risk differences between the two types of patches. This manipulation caused a similar number of guppies to use both the risky and safe feeders, reducing or offsetting the influence of risk of predation. However, the male guppies were less influenced by this manipulation than were the females. The different results for the two sexes are consistent with known differences in their life histories, indicating that a knowledge of an animal's life history will often be necessary to understand how it makes trade-offs when choosing were to forage.},
	number = {4},
	journal = {Ecology},
	author = {Mark V. Abrahams and Lawrence M. Dill},
	year = {1989},
	pages = {999--1007}
},

@article{higginson_2004a,
	title = {Accumulating wing damage affects foraging decisions in honeybees (\emph{{A}pis mellifera} {L}.)},
	volume = {29},
	issn = {03076946},
	doi = {10.1111/j.0307-6946.2004.00573.x},
	number = {1},
	journal = {Ecological Entomology},
	author = {A. D. Higginson and C. J. Barnard},
	year = {2004},
	pages = {52--59}
},

@article{higginson_2004b,
	title = {Paying for nectar with wingbeats: a new model of honeybee foraging},
	volume = {271},
	shorttitle = {Paying for nectar with wingbeats},
	doi = {10.1098/rspb.2004.2866},
	abstract = {Honeybees acquire wing damage as they age and older foraging honeybees accept lavender inflorescences with fewer flowers. These indicate the operation of some kind of optimal response, but this cannot be based on energy because energy expenditure does not change as the wings get damaged. However, wingbeat frequency increases with wing damage. A deterministic analytical model was constructed, based on the assumptions that bees have a limited total number of wingbeats that the flight motor can perform and that they maximize lifetime energy profit by conserving the number of wingbeats used in foraging. The optimal response to wing damage is to reduce the threshold number of flowers needed to accept an inflorescence. The predicted optimal gradient between wing damage (wingbeat frequency) and acceptance threshold (number of flowers on an inflorescence) was close to the observed gradient from field data. This model demonstrates that wear and tear is a significant factor in optimal foraging strategies.},
	number = {1557},
	journal = {Proceedings of the Royal Society of London, Series B},
	author = {A. D. Higginson and F. Gilbert},
	year = {2004},
	pages = {2595--2603}
},

@article{gorlick_1976,
	title = {Dominance hierarchies and factors influencing dominance in the guppy \emph{{P}oecilia reticulata} (Peters)},
	volume = {24},
	issn = {0003-3472},
	doi = {10.1016/S0003-3472(76)80041-3},
	abstract = {Dominance behaviour and factors influencing dominance were investigated in small heterosexual and homosexual groups of guppies {(Poecilia} reticulata) in the laboratory. Straight line nip-right hierarchies were the most frequent type of dominance relationship. In heterosexual groups separate homosexual hierarchies were formed, and females were the more dominant sex. Dominant males performed significantly more reproductive behaviour than lower rank individuals. Agonistic behaviour appears early in young P. reticulata. Factors involved in determining dominance were size, sex and aggressiveness. Individual or role recognition or both may occur in this species. Advantages of dominance are discussed.},
	number = {2},
	journal = {Animal Behaviour},
	author = {Dennis L. Gorlick},
	year = {1976},
	pages = {336--346}
},

@article{krause_1994,
	title = {Shoal choice in the banded killifish \emph{{F}undulus diaphanus}, {{T}eleostei, {C}yprinodontidae}): effects of predation risk, fish size, species composition and size of shoals},
	volume = {98},
	issn = {01791613},
	shorttitle = {Shoal Choice in the Banded Killifish {(Fundulus} diaphanus, Teleostei, Cyprinodontidae)},
	doi = {10.1111/j.1439-0310.1994.tb01063.x},
	abstract = {Banded killifish {(Fundulus} diaphanus) were presented individually with a choice of shoaling with either of two stimulus shoals which differed in shoal size, species composition, and fish body size, before and after a simulated avian predator attack. When threatened, test fish preferred to shoal with the larger of two conspecific shoals, but only if members of both stimulus shoals were of the same size class as the test fish. Otherwise, they preferred to shoal with similarly sized fish irrespective of shoal size; threat of predation increased the magnitude of this preference. Furthermore, test fish preferred a shoal of similarly sized shiners {(Notemigonus} crysoleucas) over larger killifish, when shoal sizes were identical. This indicates that body size plays a key role in shoal choice, overriding the effects of shoal size and species preference. Notwithstanding the above, shoal choice was affected by predator threat only when differences between shoal size or body size of stimulus fish were large.},
	number = {2},
	journal = {Ethology},
	author = {Jens Krause and {Jean-Guy} J. Godin},
	year = {1994},
	pages = {128--136}
},

@article{magurran_1994,
	title = {Predator inspection behaviour covaries with schooling tendency amongst wild guppy, \emph{{P}oecilia reticulata}, populations in {T}rinidad},
	volume = {128},
	DOI={10.1163/156853994X00073},
	issn = {00057959},
	abstract = {When fish inspect a predator they incur risk. One way of reducing the cost of inspection is to approach predators in groups large enough to benefit from the safety in numbers advantages of schooling. In a survey of nine populations of guppies, Poecilia reticulata, in their native streams in Trinidad, we observed marked variation in schooling behaviour. Guppies from sites also inhabited by a major predator, the pike cichlid, Crenicichla alta, devoted more time to schooling than those from less dangerous locations where the cyprinodont Rivulus hartii was present. We found a strong correlation between schooling tendency and the group sizes adopted by guppies inspecting a realistic model predator. Since guppies in dangerous localities approached a potential predator in large groups it seems unlikely that many of these fish were caught in a Prisoner's Dilemma. Inspections by singleton fish were rare in high-risk locations but predominated in those populations where risk from fish predators was reduced.},
	number = {1/2},
	journal = {Behaviour},
	author = {Anne E. Magurran and Benoni H. Seghers},
	year = {1994},
	pages = {121--134}
},

@article{hamilton_1971,
	title = {Geometry for the selfish herd},
	doi = {10.1016/0022-5193(71)90189-5},
	volume = {31},
	journal = {Journal of Theoretical Biology},
	author = {W D Hamilton},
	year = {1971},
	number = {2},
	pages = {295--311},
},

@article{stevens_2005b,
	title = {Will travel for food: spatial discounting in two {N}ew {W}orld primates},
	volume = {15},
	doi = {10.1016/j.cub.2005.09.016},
	abstract = {Nonhuman animals steeply discount the future, showing a preference for small, immediate over large,
delayed rewards [15]. Currently unclear is whether discounting functions depend on context. Here, we
examine the effects of spatial context on discounting in cotton-top tamarins {(Saguinus} oedipus) and common
marmosets {(Callithrix} jacchus), species known to differ in temporal discounting [5]. We presented subjects with a choice between small, nearby rewards and large, distant rewards. Tamarins traveled farther for the large reward than marmosets, attending to the ratio of reward differences rather than their absolute values. This species difference contrasts with performance on a temporal task in which marmosets waited longer than tamarins for the large reward. These comparative data indicate that context influences choice behavior, with the strongest effect seen in marmosets who discounted more steeply over space than over time. These findings parallel details of each speciesﾒ feeding ecology. Tamarins range over large distances and feed primarily on insects, which requires using quick, impulsive action. Marmosets range over shorter distances than tamarins and feed primarily on tree exudates, a clumped resource that requires patience to wait for sap to exude [69]. These results show that discounting functions are context specific, shaped by a history of ecological pressures.},
	number = {20},
	journal = {Current Biology},
	author = {Jeffrey R Stevens and Alexandra G Rosati and Kathryn R Ross and Marc D Hauser},
	year = {2005},
	pages = {1855--1860},
},

@article{agrillo_2009,
	title = {Use of number by fish},
	volume = {4},
	doi = {10.1371/journal.pone.0004786},
	abstract = {Research on human infants, mammals, birds and fish has demonstrated that rudimentary numerical abilities pre-date the evolution of human language. Yet there is controversy as to whether animals represent numbers mentally or rather base their judgments on non-numerical perceptual variables that co-vary with numerosity. To date, mental representation of number has been convincingly documented only for a few mammals.

Here we used a training procedure to investigate whether mosquitofish could learn to discriminate between two and three objects even when denied access to non-numerical information. In the first experiment, fish were trained to discriminate between two sets of geometric figures. These varied in shape, size, brightness and distance, but no control for non-numerical variables was made. Subjects were then re-tested while controlling for one non-numerical variable at a time. Total luminance of the stimuli and the sum of perimeter of figures appeared irrelevant, but performance dropped to chance level when stimuli were matched for the cumulative surface area or for the overall space occupied by the arrays, indicating that these latter cues had been spontaneously used by the fish during the learning process. In a second experiment, where the task consisted of discriminating 2 vs 3 elements with all non-numerical variables simultaneously controlled for, all subjects proved able to learn the discrimination, and interestingly they did not make more errors than the fish in Experiment 1 that could access non-numerical information in order to accomplish the task.

Mosquitofish can learn to discriminate small quantities, even when non-numerical indicators of quantity are unavailable, hence providing the first evidence that fish, like primates, can use numbers. As in humans and non-human primates, genuine counting appears to be a â€˜last resortâ€™ strategy in fish, when no other perceptual mechanism may suggest the quantity of the elements. However, our data suggest that, at least in fish, the priority of perceptual over numerical information is not related to a greater cognitive load imposed by direct numerical computation.},
	journal = {{PLoS} {ONE}},
	author = {Christian Agrillo and Marco Dadda and Giovanna Serena and Angelo Bisazza},
	year = {2009},
	number = {3},
	pages = {e4786},
},

@article{pritchard_2001,
	title = {Shoal choice in zebrafish, \emph{{D}anio rerio}: the influence of shoal size and activity},
	volume = {62},
	doi = {10.1006/anbe.2001.1858},
	abstract = {Shoaling fish are expected, in many cases, to gain fitness benefits from being in a larger shoal and previous experiments have shown that fish are indeed capable of choosing between shoals of different sizes. We investigated the influence of shoal activity on shoal size preference in the zebrafish. We gave test fish the choice between shoals of one to four stimulus fish, presented at two different water temperatures, and so differing in their activity levels. Where all stimulus fish were in water of the same temperature, test fish generally preferred the larger shoal. However, this preference could be reduced by presenting the larger shoal in colder water and so reducing its activity. We discuss these findings with reference to the factors that may influence shoal activity, the effect of temperature on shoaling behaviour and the mechanisms that may be used by fish to discriminate shoal size.},
	journal = {Animal Behaviour},
	author = {Victoria L. Pritchard and James Lawrence and Roger K. Butlin and Jens Krause},
	year = {2001},
	number = {6},
	pages = {1085--1088}
},

@article{stevens_2005a,
	title = {The ecology and evolution of patience in two {New World} monkeys},
	volume = {1},
	doi = {10.1098/rsbl.2004.0285},
	abstract = {Decision making often involves choosing between small, short-term rewards and large, long-term rewards. All animals, humans included, discount future rewards-the present value of delayed rewards is viewed as less than the value of immediate rewards. Despite its ubiquity, there exists considerable but unexplained variation between species in their capacity to wait for rewards that is, to exert patience or self-control. Using two closely related primates-common marmosets {(Callithrix} jacchus) and cotton-top tamarins {(Saguinus} oedipus)-we uncover a variable that may explain differences in how species discount future rewards. Both species faced a self-control paradigm in which individuals chose between taking an immediate small reward or waiting a variable amount of time for a large reward. Under these conditions, marmosets waited significantly longer for food than tamarins. This difference cannot be explained by life history, social behaviour, or brain size. It can, however, be explained by feeding ecology: marmosets rely on gum, a food product acquired by waiting for exudate to flow from trees, whereas tamarins feed on insects, a food product requiring impulsive action. Foraging ecology, therefore, may provide a selective pressure for the evolution of self-control.
Keywords: temporal discounting, impulsivity, rate maximization, tamarins, marmosets},
	number = {2},
	journal = {Biology Letters},
	author = {Jeffrey R Stevens and E V Hallinan and M D Hauser},
	year = {2005},
	pages = {223--226},
},

@article{evans_2006,
	title = {Self-control and tool use in tufted capuchin monkeys (\emph{{Cebus} apella})},
	volume = {120},
	doi = {10.1037/0735-7036.120.2.163},
	abstract = {Self-control is defined as forgoing immediate gratification to obtain a greater reward. Tool use may relate to self-control because both behaviors may require foresight and deliberate control over one's actions. The authors assessed 20 capuchin monkeys {(Cebus} apella) for the ability to delay gratification in a tool task. Subjects were given rod-shaped food items that could either be consumed immediately or be carried to an apparatus and used to extract a more preferred food. The authors found that some monkeys were able to exhibit self-control. Monkeys with relatively more tool use experience demonstrated the greatest levels of self-control. These results indicate that capuchins are capable of delaying gratification when a higher quality reinforcer is present and that tool experience can influence levels of self-control in this task.
Keywords: tool, self-control, capuchin, Cebus apella},
	journal = {Journal of Comparative Psychology},
	author = {T A Evans and G C Westergaard},
	year = {2006},
	number = {2},
	pages = {163--166},
},

@article{rosati_2007,
	title = {The evolutionary origins of human patience: temporal preferences in chimpanzees, bonobos, and adult humans},
	volume = {17},
	doi = {10.1016/j.cub.2007.08.033},
	abstract = {To make adaptive choices, individuals must sometimes exhibit patience, forgoing immediate benefits to acquire more valuable future rewards [1-3]. Although humans ac-count for future consequences when making temporal deci-sions [4], many animal species discount (or devalue) the future heavily [5-10]. Current research thus suggest a phy-logenetic gap between patient humans and impulsive, pre-sent-oriented animals [9, 11], a distinction with implications for our understanding of economic decision-making [12] and the origins of human cooperation [13]. Based on a se-ries of experimental results, we reject this conclusion. First, bonobos {(Pan} paniscus) and chimpanzees {(Pan} troglodytes) exhibit a degree of patience not seen in other animals tested thus far. Second, humans are less willing to wait for food rewards than are chimpanzees. Third, humans are more willing to wait for monetary rewards than for food, and show the highest degree of patience only in response to decisions about money involving low opportunity costs. These findings suggest that core components of the capacity for future-oriented decisions evolved before the human lineage diverged from apes. Moreover, the different levels of patience that humans exhibit may be driven by funda-mental differences in the mechanisms representing biologi-cal versus abstract rewards.},
	number = {19},
	journal = {Current Biology},
	author = {A G Rosati and Jeffrey R Stevens and B Hare and M D Hauser},
	year = {2007},
	pages = {1663--1668},
},

@article{pitcher_1982,
	title = {Fish in larger shoals find food faster},
	doi = {10.1007/BF00300175},
	volume = {10},
	journal = {Behavioral Ecology and Sociobiology},
	author = {T J Pitcher and A E Magurran and I J Winfield},
	year = {1982},
	number = {2},
	pages = {149--151},
},

@book{krause_2002,
	address = {Oxford},
	title = {Living in Groups},
	publisher = {Oxford University Press},
	author = {J Krause and G D Ruxton},
	year = {2002},
},

@article{hoare_2004,
	title = {Context-dependent group size choice in fish},
	volume = {67},
	issn = {0003-3472},
	doi = {10.1016/j.anbehav.2003.04.004},
	abstract = {The costs and benefits of group membership vary with the size of groups, and individuals are expected to modify their choice of groups in response to ecological factors such as food availability and predation risk. We experimentally examined context-dependent group size choice in a shoaling fish, the banded killifish, Fundulus diaphanus, by using nondirectional odour cues to simulate a food source or a successful attack by a predator (food or alarm treatments) in the laboratory. Group sizes were significantly smaller in the food treatment and larger in the alarm treatment than in control trials. When presented with food and alarm cues together, fish formed groups that were larger than control groups but smaller than those seen with alarm cues alone. These results are consistent with theoretical predictions based on the known benefits and costs of grouping and with previous laboratory work examining the individual shoal choice behaviour of single fish. To examine possible mechanisms of group formation, we developed an individual-based model of shoaling behaviour in which simulated fish were allowed to modify the area over which they interacted with neighbouring individuals. Group size distributions produced by the model were a good approximation of our experimental data. We suggest that local behavioural interaction rules of this type are a potential mechanism by which fish may individually adjust grouping behaviour without requiring extensive information on the position and movement of all possible shoalmates. {(C)} 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.},
	journal = {Animal Behaviour},
	author = {D. J. Hoare and I D Couzin and J. G. J. Godin and J. Krause},
	year = {2004},
	number = {1},
	keywords = {{BEHAVIOR;} {CYPRINODONTID} {FISH;} {SCHOOLING} {BEHAVIOR;} {TRADE-OFFS,} {KILLIFISH} {FUNDULUS-DIAPHANUS;} {SHOAL} {SIZE;} {PREDATOR} {AVOIDANCE;} {BANDED,} {KILLIFISH;} {GASTEROSTEUS-ACULEATUS;} {3-SPINED} {STICKLEBACKS;} {AGGREGATION}},
	pages = {155--164},
},

@article{hager_1991,
	title = {Safety in numbers: shoal size choice by minnows under predatory threat},
	volume = {29},
	doi = {10.1007/BF00163984},
	abstract = {Larger animal groups often provide greater protection from predators. An individual might therefore be expected to join the larger of two groups. To test this, we hypothesized that fathead minnows would choose to associate with the larger of two shoals and that the presence of a predatory largemouth bass would influence their shoal size choice. Individual minnows were presented with a series of choices between two shoal sizes, ranging from 1 to 28 fish, both with and without a predator present. Although responses were highly variable, minnows displayed an ability to choose between shoal sizes even when size differences were small, preferring the larger shoal whenever a size preference was shown. In the presence of a predator, minnows made quicker shoaling decisions and showed a strong tendency to avoid very small shoals.},
	journal = {Behavioral Ecology and Sociobiology},
	author = {Mary C. Hager and Gene S. Helfman},
	year = {1991},
	number = {4},
	pages = {271--276}
},

@article{rosati_2006,
	title = {The effect of handling time on temporal discounting in two {New World} primates},
	volume = {71},
	doi = {10.1016/j.anbehav.2005.11.012},
	abstract = {Foraging decisions in nonhuman animals often require choosing between small, immediate food rewards and larger, more delayed rewards. Faced with such choices, animals typically discount or devalue the future quite strongly. Although discounting studies often focus on delays to reward access, other temporal intervals contribute to foraging rate, and thus may potentially influence discounting levels. Here, we examine the effect of handling time, the time required to process and consume food, on discounting in cottontop tamarins, Saguinus oedipus, and common marmosets, Callithrix jacchus, two species that differ in levels of temporal discounting. We presented subjects with a discounting task under two conditions. In the first condition, we made the entire reward available after the delay expired. In the second condition, we experimentally increased the minimum length of time required to consume the reward to simulate a longer handling time. We found that tamarins and marmosets showed sensitivity to increases in the time necessary to process food rewards. Both species adjusted their preferences to account for different handling times at long delays to accessing food. Consequently, models of discounting behaviour that include handling times may better describe animal choices than models that focus exclusively on delays prior to access.},
	number = {6},
	journal = {Animal Behaviour},
	author = {Alexandra G Rosati and Jeffrey R Stevens and Marc D Hauser},
	year = {2006},
	pages = {1379--1387},
},

@inbook{sweave_2002,
  title={Sweave: dynamic generation of statistical reports using literate data analysis},
  booktitle={Compstat 2002---{Proceedings in Computational Statistics}},
  publisher={Physica Verlag},
  address={Heidelberg},
  author={Leisch, Friedrich},
  editor={H\"{a}rdle, Wolfgang and R\"{o}nz, BerndEditors},
  year={2002},
  pages={575--580}
},

@article{agrillo_2007b,
  title={Quantity discrimination in female mosquitofish},
  volume={10},
  doi = {10.1007/s10071-006-0036-5},
  abstract={Abstract  The ability in animals to count and represent different numbers of objects has received a great deal of attention in the past few decades. Cumulative evidence from comparative studies on number discriminations report obvious analogies among human babies, non-human primates and birds and are consistent with the hypothesis of two distinct and widespread mechanisms, one for counting small numbers (<4) precisely, and one for quantifying large numbers approximately. We investigated the ability to discriminate among different numerosities, in a distantly related species, the mosquitofish, by using the spontaneous choice of a gravid female to join large groups of females as protection from a sexually harassing male. In one experiment, we found that females were able to discriminate between two shoals with a 1:2 numerosity ratio (2 vs. 4, 4 vs. 8 and 8 vs. 16 fish) but failed to discriminate a 2:3 ratio (8 vs. 12 fish). In the second experiment, we studied the ability to discriminate between shoals that differed by one element; females were able to select the larger shoal when the paired numbers were 2 vs. 3 or 3 vs. 4 but not 4 vs. 5 or 5 vs. 6. Our study indicates that numerical abilities in fish are comparable with those of other non-verbal creatures studied; results are in agreement with the hypothesis of the existence of two distinct systems for quantity discrimination in vertebrates.},
  number={1},
  journal={Animal Cognition},
  author={Agrillo, Christian and Dadda, Marco and Bisazza, Angelo},
  year={2007},
  pages={63--70}
},

@article{agrillo_2008,
  title={Do fish count? {S}pontaneous discrimination of quantity in female mosquitofish},
  volume={11},
  doi = {10.1007/s10071-008-0140-9},
  abstract={Abstract  The spontaneous tendency to join the largest social group was used to investigate quantity discrimination in fish. Fish discriminated between shoals that differed by one element when the paired numbers were 1vs2, 2vs3 and 3vs4, but not when 4vs5 or larger. Using large numerosities (>4), the ability to discriminate between two numbers improved as the numerical distance between them increased and a significant discrimination was found only with ratios of 1:2 or smaller (4vs8, 8vs16 and 4vs10). Experiments to control for non-numerical variables evidenced the role played by the total area of stimuli with both large and small numerosities; the total quantity of movement of the fish within a shoal appeared also important but only when large numerosities were involved. Even though the pattern of discrimination exhibited by female mosquitofish is not fully consistent with any of the existing models of quantity representation, our results seem to suggest two distinct mechanisms in fish, one used to compare small numbers of objects and one used when larger numerosities are involved.},
  number={3},
  journal={Animal Cognition},
  author={Agrillo, Christian and Dadda, Marco and Serena, Giovanna and Bisazza, Angelo},
  year={2008},
  pages={495-503}
},
﻿
@techreport{de_leeuw_2001,
	address = {Los Angeles},
	title = {Reproducible research: the bottom line},
	institution = {{UCLA}},
	author = {J de Leeuw},
	year = {2001}
},

@article{smith_1992,
	title = {Alarm signals in fishes},
	volume = {2},
	issn = {0960-3166},
	doi = {10.1007/BF00042916},
	number = {1},
	journal = {Reviews in Fish Biology and Fisheries},
	author = {R. Jan F. Smith},
	year = {1992},
	pages = {33--63}
},

@article{tegeder_1995,
	title = {Density dependence and numerosity in fright stimulated aggregation behaviour of shoaling fish},
	volume = {350},
	doi = {10.1098/rstb.1995.0172},
	abstract = {Single three-spined sticklebacks, Gasterosteus aculeatus, were frightened with a light stimulus simulating an aerial predator while facing a choice between two conspecific display shoals of different membership sizes. We observed which shoal the test fish approached. Initially, both display shoals were equidistant from the test fish. The smaller shoal was then moved gradually closer whereas the larger shoal stayed at a constant distance. This experiment modelled an early stage of the aggregation behaviour of sticklebacks in response to perceived imminent predation risk. When the two display shoals were equidistant from the test fish, we found that the test animal preferred approaching the larger display shoal, and the magnitude of this preference increased with increasing display shoal size difference. This demonstrates that the aggregation behaviour of frightened sticklebacks is density dependent. Further, we found that sticklebacks made a trade-off between the distance to a display shoal and its membership size. In particular, for a given ratio of display shoal sizes, there was a critical distance at which half of all tested animals turned to one and the other half to the other display shoal. This demonstrates that the observed aggregation behaviour is also distance dependent. We introduce several elementary models which formalize individual predation risk and explore how distance and display shoal size contribute to total risk. In particular, we distinguish between total risk as a product or as a sum of the risk components associated with swimming distance and display shoal size, respectively. All models follow the `partial preferences' paradigm of {McNamara} \& Houston {(Anim.} Behav. 35, 1084-1099 (1987)). We compare how closely these models match the observed data and how well they predict the empirical critical distances. We find a consistent discrepancy between theory and data, which we resolve by invoking a fundamental perceptual limit (numerosity) for shoal size discrimination.},
	number = {1334},
	journal = {Philosophical Transactions of the Royal Society of London, Series B},
	author = {Roland W. Tegeder and Jens Krause},
	year = {1995},
	pages = {381--390},
},

@article{richards_determination_1997,
	title = {Determination of discount functions in rats with an adjusting-amount procedure},
	volume = {67},
	doi = {10.1901/jeab.1997.67-353.},
	abstract = {An adjusting-amount procedure was used to measure discounting of reinforcer value by delay. Eight rats chose between a varying amount of immediate water and a fixed amount of water given after a delay. The amount of immediate water was systematically adjusted as a function of the rats' previous choices. This procedure was used to determine the indifference point at which each rat chose the immediate amount and the delayed amount with equal frequency. The amount of immediate water at this indifference point was used to estimate the value of the delayed amount of water. In Experiment 1, the effects of daily changes in the delay to the fixed reinforcer (100 µl of water delivered after 0, 2, 4, 8, or 16 s) were tested. Under these conditions, the rats reached indifference points within the first 30 trials of each 60-trial session. In Experiment 2, the effects of water deprivation level on discounting of value by delay were assessed. Altering water deprivation level affected the speed of responding but did not affect delay discounting. In Experiment 3, the effects of varying the magnitude of the delayed water (100, 150, and 200 µl) were tested. There was some tendency for the discounting function to be steeper for larger than for smaller reinforcers, although this difference did not reach statistical significance. In all three experiments, the obtained discount functions were well described by a hyperbolic function. These experiments demonstrate that the adjusting-amount procedure provides a useful tool for measuring the discounting of reinforcer value by delay.},
	journal = {Journal of the Experimental Analysis of Behavior},
	author = {J B Richards and S H Mitchell and H de Wit and L S Seiden},
	year = {1997},
	number = {3},
	pages = {353--366},
}


@article{vick_2010,
	title = {How do {A}frican grey parrots (\emph{{P}sittacus erithacus}) perform on a delay of gratification task?},
	volume = {13},
	doi = {10.1007/s10071-009-0284-2},
	abstract = {Abstract  Humans and other animals often find it difficult to choose a delayed reward over an immediate one, even when the delay leads
to increased pay-offs. Using a visible incremental reward procedure, we tested the ability of three grey parrots to maintain
delay of gratification for an increasingly valuable food pay-off. Up to five sunflower seeds were placed within the parrot’s
reach, one at a time, at a rate of one seed per second. When the parrot took a seed the trial was ended and the birds consumed
the accumulated seeds. Parrots were first tested in daily sessions of ten trials and then with single daily trials. For multiple
trial sessions, all three parrots showed some limited improvement across 30 sessions. For single trial sessions, only one
parrot showed any increase in seed acquisition across trials. This parrot was also able to consistently obtain two or more
seeds per trial (across both multiple and single trial conditions) but was unable to able to wait 5 s to obtain the maximum
number of seeds. This parrot was also tested on a slower rate of seed presentation, and this significantly reduced her mean
seed acquisition in both multiple and single trial conditions, suggesting that both value of reward available and delay duration
impact upon self-control. Further manipulation of both the visibility and proximity of seeds during delay maintenance had
little impact upon tolerance of delays for both parrots tested in this condition. This task demanded not just a choice of
delayed reward but the maintenance of delayed gratification and was clearly difficult for the parrots to learn; additional
training or alternative paradigms are required to better understand the capacity for self-control in this and other species.},
	number = {2},
	journal = {Animal Cognition},
	author = {{Sarah-Jane} Vick and Dalila Bovet and James Anderson},
	year = {2010},
	pages = {351--358}
},

@article{hardisty_2009,
	title = {Discounting future green: money versus the environment.},
	volume = {138},
	issn = {1939-2222},
	shorttitle = {Discounting future green},
	doi = {10.1037/a0016433},
	abstract = {In 3 studies, participants made choices between hypothetical financial, environmental, and health gains and losses that took effect either immediately or with a delay of 1 or 10 years. In all 3 domains, choices indicated that gains were discounted more than losses. There were no significant differences in the discounting of monetary and environmental outcomes, but health gains were discounted more and health losses were discounted less than gains or losses in the other 2 domains. Correlations between implicit discount rates for these different choices suggest that discount rates are influenced more by the valence of outcomes (gains vs. losses) than by domain (money, environment, or health). Overall, results indicate that when controlling as many factors as possible, at short to medium delays, environmental outcomes are discounted in a similar way to financial outcomes, which is good news for researchers and policy makers alike. {(PsycINFO} Database Record (c) 2009 {APA,} all rights reserved)},
	number = {3},
	journal = {Journal of Experimental Psychology: General},
	author = {David J. Hardisty and Elke U. Weber},
	year = {2009},
	pages = {329--340}
},

@article{chapman_1995,
	title = {Valuing the future: temporal discounting of health and money},
	volume = {15},
	doi = {10.1177/0272989X9501500408},
	abstract = {Normative discounted utility theory specifies that the values of all future outcomes (for example, those related to health and money) should be discounted at a constant rate. Two experiments demonstrated that, contrary to this prescription, decision makers use different discount rates for health-related decisions and money-related decisions. Temporal discount ings for health and money were similar in that both demonstrated two biases previously found in monetary decisions: discount rates were inversely related to magnitude of outcome and length of delay. The relatively large discount rates used by the subjects suggest why it is often difficult to implement preventive health measures that improve future health. Key words: discounting; intertemporal choice; health decisions. {(Med} Decis Making 1995;15:373- 386)},
	number = {4},
	journal = {Medical Decision Making},
	author = {Gretchen B. Chapman and Arthur S. Elstein},
	year = {1995},
	pages = {373--386}
},

@article{day_2001,
	title = {Interactions between shoal size and conformity in guppy social foraging},
	volume = {62},
	issn = {0003-3472},
	doi = {10.1006/anbe.2001.1820},
	abstract = {Previous experimental studies have established that shoaling fish forage more effectively in large than small groups. We investigated how shoal size affects the foraging efficiency of laboratory populations of the guppy, Poecilia reticulata, exposed to different foraging tasks. Experiment 1 confirmed the prediction that in open water the first fish and focal fish of larger shoals locate food faster than in smaller shoals. However, a second experiment, in which shoals of fish were required to swim through a hole in an opaque partition to locate food, found the reverse pattern: smaller shoals learned to complete the task faster than large shoals. Experiment 3, in which shoals of various sizes were exposed to a transparent maze partition, clarified the apparent contradictory results of the first two experiments, with larger shoals again learning to complete the task faster than small shoals. The findings of experiments 2 and 3 can be explained in terms of positive frequency-dependent social learning, or conformity. This facilitated social learning in large groups in experiment 3 where visual contact could be maintained through the partition, but hindered it in experiment 2 where visual contact was lost once a fish had passed through the partition. The findings raise the possibility that novel behavioural innovations, particularly those that require individuals to break contact with the group, may be more likely to spread in smaller than larger groups of animals.},
	number = {5},
	journal = {Animal Behaviour},
	author = {Rachel L. Day and Tom {MacDonald} and Culum Brown and Kevin N. Laland and Simon M. Reader},
	year = {2001},
	pages = {917--925}
},

@article{laland_1997,
	title = {Shoaling generates social learning of foraging information in guppies},
	volume = {53},
	doi = {10.1006/anbe.1996.0318},
	abstract = {Two experimental studies are reported which investigate the social learning of foraging information in {guppies,Poecilia} {reticulataIn} both cases, untrained adult female guppies swam with trained conspecifics to feed, and in the process learned a route to a food source. In experiment 1, subjects were given 5 days experience swimming with demonstrator fish trained to take one of two equivalent routes to food. When tested alone, subjects preferentially used the route of their demonstrators. Experiment 2 investigated whether this social learning could mediate the stable transmission of route preferences among small populations of fish. This experiment used a transmission chain design, in which fish in small founder populations were trained to take one of the two routes, with founder members gradually replaced by untrained conspecifics. Three days after all founder members had been removed, populations of untrained fish still maintained strong preferences for the routes of their founders. The results suggest that the tendency to shoal may facilitate a simple form of guided social learning, which allows guppies to learn about their local environments. They also imply that selectively neutral behavioural alternatives may be maintained as traditions in aggregated animal populations by very simple social mechanisms. The transmission chain method may be particularly useful for studying social species, such as the guppy, that do not respond well to isolation testing.},
	number = {6},
	journal = {Animal Behaviour},
	author = {Kevin N Laland and Kerry Williams},
	year = {1997},
	pages = {1161--1169}
},

@article{pearson_2010,
	title = {Explicit information reduces discounting behavior in monkeys},
	volume = {1},
	doi = {10.3389/fpsyg.2010.00237},
	journal = {Frontiers in Psychology},
	author = {J M Pearson and B Y Hayden and M L Platt},
	year = {2010},
	pages = {237}
},

@article{dussault_1981,
	title = {Food and feeding behavior of the guppy, \emph{{P}oecilia reticulata} ({P}isces: {P}oeciliidae)},
	volume = {59},
	doi = {10.1139/z81-098},
	number = {4},
	journal = {Canadian Journal of Zoology},
	author = {Gertrude V. Dussault and Donald L. Kramer},
	year = {1981},
	pages = {684--701}
},

@article{ashley_1993,
	title = {Balancing trade-offs between risk and changing shoal size in {N}orthern red-belly dace (\emph{{P}hoxinus eos)}},
	volume = {1993},
	issn = {00458511},
	number = {2},
	journal = {Copeia},
	author = {Eric J. Ashley and Lee B. Kats and James W. Wolfe},
	year = {1993},
	pages = {540--542}
},

@article{noser_2007,
	title = {Travel routes and planning of visits to out-of-sight resources in wild chacma baboons, \emph{{P}apio ursinus}},
	volume = {73},
	doi = {doi:10.1016/j.anbehav.2006.04.012},
	abstract = {The ability of animals to plan their foraging journeys and to approach resources in a goal-directed way may play a key role in cognitive evolution. Furthermore, optimal foraging theory assumes that animals are adapted to take least-effort routes between resources. Empirical evidence for these beliefs is largely lacking, however. We followed a group of chacma baboons over full days during a 16-month field study. We used {GPS} to investigate route linearity, travel speed and inter-resource distances, and the degree to which movement was guided by direct visual stimuli from the resources. During the dry season the study group travelled rapidly to sparse fruit sources and waterholes along linear paths over large distances. Inter-resource distances were larger than distances from which the resources could be seen. Seed resources, although situated closer to the sleeping site than fruit sources, were bypassed in the mornings and consumed predominantly in the afternoons, when movements were less linear, slower and shorter. During the rainy season, the animals left their sleeping sites earlier when visiting restricted and patchily distributed fig trees than when visiting abundant and evenly distributed fruit resources. However, travel speed and route linearity were not always associated with goal directedness, because the baboons approached the single sleeping site, presumably a vital resource, slowly and indirectly. Our results suggest that baboons plan their journeys, actively choosing between several out-of-sight resources and approaching them in an efficient, goal-directed way, characteristics commonly used as diagnostic for the presence of a cognitive map and episodic memory.},
	journal = {Animal Behaviour},
	author = {R Noser and R W Byrne},
	year = {2007},
	number = {2},
	keywords = {chacma baboons, cognitive map, Episodic memory, goal-directed behaviour, Papio ursinus, travel routes},
	pages = {257--266}
},

@incollection{stevens_2009,
	address = {Washington, {DC}},
	title = {The adaptive nature of impulsivity},
	isbn = {978-1-4338-0477-9},
	booktitle = {Impulsivity: The Behavioral and Neurological Science of Discounting},
	publisher = {American Psychological Association},
	author = {Jeffrey R Stevens and David W Stephens},
	editor = {Gregory J Madden and Warren K Bickel},
	year = {2009},
	pages = {361--387},
	file = {Full Text (PDF):undefined:application/pdf}
},

@article{odum_2006,
	title = {Discounting of delayed hypothetical money and food: effects of amount},
	volume = {73},
	doi = {10.1016/j.beproc.2006.06.008},
	abstract = {Delay discounting research determines how the value of an outcome is affected by delay to its receipt. Research so far shows that consumable outcomes are discounted more steeply by delay than money. Prior studies, however, have used large amounts of the outcomes (e.g. \$100 worth) that would not typically be consumed in one bout, unlike the corresponding amount of money (e.g. \$100). This experiment examined whether small amounts of food would be discounted more steeply than money, as occurs with larger amounts. One hundred and two adults indicated their preferences in a series of choices for two hypothetical outcome types: immediate versus delayed food and immediate versus delayed money. Participants made choices involving either relatively small maximum amounts of food (\$10 worth) and money (\$10) or for relatively large maximum amounts of food (\$100 worth) and money (\$100). In the within-subject comparisons, food was discounted more steeply by delay than money for both groups. In the between-subject comparisons, different amounts of the commodities were affected similarly by delay. Overall, these results suggest that steeper discounting of consumable outcomes than money is a fairly robust phenomenon, occurring with relatively small amounts of outcomes as well as with larger amounts.},
	journal = {Behavioural Processes},
	author = {A L Odum and A A L Baumann and D D Rimington},
	year = {2006},
	number = {3},
	keywords = {Consumable, Delay discounting, Food, impulsivity, Money, Self-control},
	pages = {278}
},

@article{ainslie_1974,
	title = {Impulse control in pigeons},
	volume = {21},
	doi = {10.1901/jeab.1974.21-485},
	journal = {Journal of the Experimental Analysis of Behavior},
	author = {G Ainslie},
	year = {1974},
	number = {3},
	pages = {485--489}
},

@article{abeyesinghe_2005,
	title = {Can domestic fowl, \emph{{G}allus gallus domesticus}, show self-control?},
	volume = {70},
	doi = {10.1016/j.anbehav.2004.10.011},
	abstract = {An important aspect of cognition is whether animals live exclusively in the present or can anticipate the future. Defined as self-control, the ability to choose a large, remote reinforcer over a small, proximate reinforcer available at the same frequency has been examined in a number of species, often proving difficult to demonstrate. We investigated self-control for food in domestic fowl using a standard two-key operant task and an equivalent two-choice return maze {(TCRM)} task. When hens chose between a 2-s delay to a 3-s feed access (impulsive) and a 6-s delay to a 7-s feed access (self-control), they appeared unable to discriminate in the {TCRM} but were impulsive in the operant task. We explored reasons for not choosing self-control in the operant task, first by examining the relation between feed access time and actual feed intake. A second operant experiment examined whether failure to show self-control could be attributed to an inability to combine the delay and access (quantity) reward information associated with choices to reach overall predictions of value. New hens chose between a 2-s delay to a 3-s feed access (impulsive) and either a 22-s delay to a 22-s feed access (standard self-control) or a 6-s delay to a 22-s feed access (jackpot self-control). While hens were impulsive in the standard condition, they showed significant and pronounced self-control in the jackpot condition, eliminating the possibility of an absolute cognitive constraint. Impulsive behaviour can instead be explained by temporal discounting: perceived depreciation of reward value as a function of the uncertainty associated with delay. Implications for welfare are discussed.},
	number = {1},
	journal = {Animal Behaviour},
	author = {S M Abeyesinghe and C J Nicol and S J Hartnell and C M Wathes},
	year = {2005},
	pages = {1--11}
},

@article{bateson_1996,
	title = {Rate currencies and the foraging starling: the fallacy of the averages revisited},
	volume = {7},
	doi = {10.1093/beheco/7.3.341},
	journal = {Behavioral Ecology},
	author = {M Bateson and A Kacelnik},
	year = {1996},
	number = {3},
	pages = {341--352}
},

@article{evans_2007,
	title = {Chimpanzees use self-distraction to cope with impulsivity},
	volume = {3},
	doi = {10.1098/rsbl.2007.0399},
	abstract = {It is unknown whether animals, like humans, can employ behavioural strategies to cope with impulsivity. To examine this question, we tested whether chimpanzees {(Pan} troglodytes) would use self-distraction as a coping strategy in a situation in which they had to continually inhibit responses to accumulating candies in order to earn a greater amount of those rewards. We tested animals in three conditions in which they were sometimes given a set of toys and were sometimes allowed physical access to the accumulating candies. Chimpanzees allowed the rewards to accumulate longer before responding when they could divert their attention to the toys, and they manipulated the toys more when the candies were physically accessible. Thus, chimpanzees engaged in self-distraction with the toys when such behaviour was most beneficial as a coping mechanism.},
	journal = {Biology Letters},
	author = {T A Evans and M J Beran},
	year = {2007},
	number = {6},
	pages = {599--602}
},

@article{richards_1997,
	title = {Determination of discount functions in rats with an adjusting-amount procedure},
	volume = {67},
	doi = {10.1901/jeab.1997.67-353},
	abstract = {An adjusting-amount procedure was used to measure discounting of reinforcer value by delay. Eight rats chose between a varying amount of immediate water and a fixed amount of water given after a delay. The amount of immediate water was systematically adjusted as a function of the rats' previous choices. This procedure was used to determine the indifference point at which each rat chose the immediate amount and the delayed amount with equal frequency. The amount of immediate water at this indifference point was used to estimate the value of the delayed amount of water. In Experiment 1, the effects of daily changes in the delay to the fixed reinforcer (100 µl of water delivered after 0, 2, 4, 8, or 16 s) were tested. Under these conditions, the rats reached indifference points within the first 30 trials of each 60-trial session. In Experiment 2, the effects of water deprivation level on discounting of value by delay were assessed. Altering water deprivation level affected the speed of responding but did not affect delay discounting. In Experiment 3, the effects of varying the magnitude of the delayed water (100, 150, and 200 µl) were tested. There was some tendency for the discounting function to be steeper for larger than for smaller reinforcers, although this difference did not reach statistical significance. In all three experiments, the obtained discount functions were well described by a hyperbolic function. These experiments demonstrate that the adjusting-amount procedure provides a useful tool for measuring the discounting of reinforcer value by delay.},
	journal = {Journal of the Experimental Analysis of Behavior},
	author = {J B Richards and S H Mitchell and H de Wit and L S Seiden},
	year = {1997},
	number = {3},
	pages = {353--366}
},

@article{tobin_1994,
	title = {Self-control across species (\emph{{Columba} livia}, \emph{{Homo} sapiens}, and \emph{{Rattus} norvegicus})},
	volume = {108},
	doi = {10.1037/0735-7036.108.2.126},
	abstract = {Data from 6 previous studies of self-control behavior were compared against predictions made by the matching law and by molar maximization. The studies involved pigeons {(Columba} livia), rats {(Rattus} norvegicus), and 3-yr-old, 5-yr-old, and adult humans {(Homo} sapiens) who had received food as the reinforcer, and adult humans who had received points exchangeable for money as the reinforcer. Neither theory proved to be an accurate or better predictor for all groups. In contrast to the predictions of these theories, self-control was shown to vary according to species, human age group, and reinforcer quality. When the reinforcer was food, the self-control of different species was found to be negatively correlated with metabolic rate; that is, larger species showed greater self-control. These results suggest that allometric scaling may prove useful in describing and predicting species differences in self-control. {(PsycINFO} Database Record (c) 2000 {APA,} all rights reserved) (unassigned).},
	journal = {Journal of Comparative Psychology},
	author = {H Tobin and A W Logue},
	year = {1994},
	number = {2},
	pages = {126--133}
},
﻿
@article{laland_1999b,
	title = {Foraging innovation is inversely related to competitive ability in male but not in female guppies},
	volume = {10},
	doi = {10.1093/beheco/10.3.270},
	abstract = {Foraging success is likely to affect hunger level and motivation to locate
and exploit novel food sources in animals. We explored the relationship
between scramble competition for limited food and foraging innovation in the
guppy {(Poecilia} reticulata), predicting that poor competitors would
be more likely to innovate when presented with novel foraging tasks. Among
males, we found that latency to complete novel foraging tasks was correlated
both with weight gain and number of food items consumed, suggesting that poor
competitors are more likely to innovate. However, among females there was no
relationship between innovative tendency and either weight gain or foraging
success. We suggest that this sex difference may reflect parental investment
asymmetries in males and females, and we predict similar sex differences in
other species.},
	number = {3},
	journal = {Behavioral Ecology},
	author = {Kevin N. Laland and Simon M. Reader},
	year = {1999},
	pages = {270 --274}
},

@article{laland_1999a,
	title = {Foraging innovation in the guppy},
	volume = {57},
	issn = {0003-3472},
	doi = {10.1006/anbe.1998.0967},
	abstract = {When novel behaviour patterns spread through animal populations, typically one animal will initiate the diffusion. It is not known whether such [`]innovators' are particularly creative individuals, individuals exposed to the appropriate environmental contingencies, or individuals in a particular motivational state. We describe three experiments that investigated the factors influencing foraging innovation in the {guppyPoecilia} reticulata. We exposed small laboratory populations of fish to novel foraging tasks, which involved exploration and problem solving to locate a novel food source. Experiments 1 and 2 found that (1) females were more likely to innovate than males, (2) food-deprived fish were more likely to innovate than nonfood-deprived subjects, and (3) smaller fish were more likely to innovate than larger fish. We suggest that the sex difference may reflect parental investment asymmetries in males and females. Experiment 3 found that past innovators were more likely to innovate than past noninnovators. Collectively, the results suggest that differences in foraging innovation in guppies are best accounted for by differences in motivational state, but, in addition, guppies may vary in their predisposition to innovate.},
	number = {2},
	journal = {Animal Behaviour},
	author = {K N Laland and S M Reader},
	year = {1999},
	pages = {331--340}
},

@article{reader_2000,
	title = {Diffusion of foraging innovations in the guppy},
	volume = {60},
	issn = {0003-3472},
	doi = {10.1006/anbe.2000.1450},
	abstract = {The way in which novel learned behaviour patterns spread through animal populations remains poorly understood, despite extensive field research and the recognition that such processes play an important role in the behavioural development, social interactions and evolution of many animal species. We conducted a series of controlled diffusions of foraging information in replicate experimental populations of the guppy, Poecilia reticulata. We presented novel foraging tasks over 15 trials to mixed-sex groups, made up of food-deprived and nonfood-deprived adults (experiment 1) or small, young fish and old, large adults (experiment 2). In these diffusions, knowledge of a route to a feeder could spread through the group by subjects learning from others, discovering the route for themselves, or, most likely, by some combination of these social and asocial learning processes. We found a striking sex difference, with novel foraging information spreading at a significantly faster rate through subgroups of females than of males. Females both discovered the goal and learned the route more quickly than males. Food-deprived individuals were faster at completing the tasks over the 15 trials than nonfood-deprived guppies, and there was a significant interaction between sex and size, with a sex difference in adults but not young individuals. There was also an interaction between sex and hunger level, with food deprivation having a stronger effect on male than female performance. We suggest that information may diffuse in a similar nonrandom or [`]directed' manner through many natural populations of animals.},
	number = {2},
	journal = {Animal Behaviour},
	author = {Simon M. Reader and Kevin N. Laland},
	year = {2000},
	pages = {175--180}
},

@article{todd_2007,
	title = {Environments that make us smart: ecological rationality},
	volume = {16},
	doi = {10.1111/j.1467-8721.2007.00497.x},
	abstract = {{ABSTRACT-} Traditional views of rationality posit general-purpose decision mechanisms based on logic or optimization. The study of ecological rationality focuses on uncovering the "adaptive toolbox" of domain-specific simple heuristics that real, computationally bounded minds employ, and explaining how these heuristics produce accurate decisions by exploiting the structures of information in the environments in which they are applied. Knowing when and how people use particular heuristics can facilitate the shaping of environments to engender better decisions.},
	number = {3},
	journal = {Current Directions in Psychological Science},
	author = {P M Todd and G Gigerenzer},
	year = {2007},
	pages = {167--171}
},

@article{stephens_2001,
	title = {The adaptive value of preference for immediacy: when shortsighted rules have farsighted consequences},
	volume = {12},
	doi = {10.1093/beheco/12.3.330},
	abstract = {Results from the operant laboratory suggest that short-term benefits guide animal feeding decisions. These results appear to contradict evolutionarily-motivated models of foraging that emphasize long-term benefits. Because of this contradiction, some behavioral ecologists argue that natural selection must favor short-term benefits in some unknown way. This study addresses the contradiction by testing the feeding preferences of captive blue jays in two economically equivalent situations. The first situation follows the operant literature's “self-control” paradigm; jays make a binary choice between small-immediate and large-delayed options. The second situation is modeled on patch-use problems; the jays make a leave-stay decision in which “leaving” leads to small amount in a short time, and “staying” leads to larger amount in a longer time. In the self-control situations, the observed outcome agrees with short-term rate maximizing, as other investigators have reported. In the patch situation, the results agree more closely with long-term rate maximizing. The text explains how a rule of preference based on short-term rate comparisons can account for both situations. It is argued that natural selection may have favored short-term rules because they have long-term consequences in many natural foraging situations.},
	number = {3},
	journal = {Behavioral Ecology},
	author = {David W Stephens and D Anderson},
	year = {2001},
	keywords = {blue jay, foraging, prey, self-control},
	pages = {330--339}
},


@article{louie_2010,
	title = {Separating value from choice: delay discounting activity in the lateral intraparietal area},
	volume = {30},
	shorttitle = {Separating Value from Choice},
	url = {http://www.jneurosci.org/cgi/content/abstract/30/16/5498},
	doi = {10.1523/JNEUROSCI.5742-09.2010},
	abstract = {The mathematical formulations used to study the neurophysiological signals governing choice behavior fall under one of two major theoretical frameworks: "choice probability" or "subjective value." These two formulations represent behavioral quantities closely tied to the decision process, but it is unknown whether one of these variables, or both, dominates the neural mechanisms that mediate choice. Value and choice probability are difficult to distinguish in practice, because higher-valued options are chosen more frequently in free-choice tasks. This distinction is particularly relevant for sensorimotor areas such as parietal cortex, where both value information and motor signals related to choice have been observed. We recorded the activity of neurons in the lateral intraparietal area while monkeys performed an intertemporal choice task for rewards differing in delay to reinforcement. Here we show that the activity of parietal neurons is precisely correlated with the individual-specific discounted value of delayed rewards, with peak subjective value modulation occurring early in task trials. In contrast, late in the decision process these same neurons transition to encode the selected action. When directly compared, the strong delay-related modulation early during decision making is driven by subjective value rather than the monkey's probability of choice. These findings show that in addition to information about gains, parietal cortex also incorporates information about delay into a precise physiological correlate of economic value functions, independent of the probability of choice.},
	number = {16},
	journal = {Journal of Neuroscience},
	author = {Kenway Louie and Paul W. Glimcher},
	year = {2010},
	pages = {5498--5507}
},

@article{woolverton_2007,
	title = {Delay discounting of cocaine by rhesus monkeys},
	volume = {15},
	issn = {1064-1297},
	url = {http://www.sciencedirect.com/science/article/B6WYY-4P2XG3M-3/2/5e7af4730ae4846586ac1fcc09c1ceb9},
	doi = {10.1037/1064-1297.15.3.238},
	abstract = {The present, subjective value of a reinforcer typically decreases as a function of the delay to its receipt, a phenomenon termed delay discounting. Delay discounting, which is assumed to reflect impulsivity, is hypothesized to play an important role in drug abuse. The present study examined delay discounting of cocaine injections by rhesus monkeys. Subjects were studied on a discrete-trials task in which they chose between 2 doses of cocaine: a smaller, immediate dose and a larger, delayed dose. The immediate dose varied between 0.012 and 0.4 mg/kg/ injection, whereas the delayed dose was always 0.2 mg/kg/injection and was delivered after a delay that varied between 0 and 300 s in different conditions. At each delay, the point at which a monkey chose the immediate and delayed doses equally often (i.e., the {ED50)} provided a measure of the present, subjective value of the delayed dose. Dose-response functions for the immediate dose shifted to the left as delay increased. The amount of the immediate dose predicted to be equal in subjective value to the delayed dose decreased as a function of the delay, and hyperbolic discounting functions provided good fits to the data (median R2 = .86). The current approach may provide the basis for an animal model of the effect of delay on the subjective value of drugs of abuse.},
	number = {3},
	journal = {Experimental and Clinical Psychopharmacology},
	author = {William L. Woolverton and Joel Myerson and Leonard Green},
	year = {2007},
	keywords = {Choice, cocaine, Delay discounting, impulsivity, monkeys},
	pages = {238--244}
},

@article{perrings_2001,
	title = {An introduction to spatial discounting},
	volume = {41},
	issn = {0022-4146},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/0022-4146.00205/abstract},
	doi = {10.1111/0022-4146.00205},
	abstract = {Research on the valuation of environmental externalities shows that decision makers tend to discount not only over time but across space. Just as time discounting has implications for intergenerational equity, geographical or spatial discounting has implications for intragenerational equity. Similarly, just as positive time discount rates are warranted by positive net rates of growth of the capital stock, positive spatial discount rates may be warranted by the fact that enviironmental (or other external effects of economic activity are diffused at positive rates. This paper introduces the notion of spatial discounting and explores its welfare implications through a simple diffusion model.},
	number = {1},
	journal = {Journal of Regional Science},
	author = {Charles Perrings and Bruce Hannon},
	year = {2001},
	pages = {23--38}
},

@article{smith_1975,
	title = {An axiomatic theory of spatial discounting behavior},
	volume = {35},
	issn = {1056-8190},
	url = {http://www.springerlink.com/content/vlm3010156142024/},
	doi = {10.1007/BF01947466},
	number = {1},
	journal = {Papers of the Regional Science Association},
	author = {Tony E. Smith},
	year = {1975},
	pages = {31--44}
},

@incollection{kacelnik_2003,
	address = {New York},
	title = {The evolution of patience},
	isbn = {978-0-87154-549-7},
	url = {http://www.russellsage.org/publications/books/0-87154-549-7},
	booktitle = {Time and Decision: Economic and Psychological Perspectives on Intertemporal Choice},
	publisher = {Russell Sage Foundation},
	author = {A Kacelnik},
	editor = {G Loewenstein and D Read and R F Baumeister},
	year = {2003},
	keywords = {discounting},
	pages = {115--138}
},

@article{janson_2007,
	title = {Experimental evidence for route integration and strategic planning in wild capuchin monkeys},
	volume = {10},
	url = {http://dx.doi.org/10.1007/s10071-007-0079-2},
	doi = {10.1007/s10071-007-0079-2},
	abstract = {Abstract  Both in captivity and the wild, primates are found to travel mostly to the nearest available resource, but they may skip over the closest resource and travel to more distant resources, which are often found to be more productive. This study examines the tradeoff between distance and reward in the foraging choices of one group of wild capuchin monkeys {(Cebus} apella nigritus) using feeding platforms in large-scale foraging experiments conducted over four years. Three feeding sites were arrayed in an oblique triangle, such that once the monkey group had chosen one site to feed, they had a choice between two remaining sites, a close one with less food and the other up to 2.3 times as far away but with more food. Sites were provisioned once per day. The capuchins generally chose the closer feeding site, even when the more distant site offered up to 12 times as much food. The distances to, rewards of, or various profitability measures applied to each alternative site individually did not explain the group’s choices in ways consistent with foraging theory or principles of operant psychology. The group’s site choices were predicted only by comparing efficiency measures of entire foraging pathways: (1) direct travel to the more rewarding distant site, versus (2) the longer ‘detour’ through the closer site on the way to the more distant one. The group chose the detour more often when the reward was larger and the added detour distance shorter. They appeared to be more sensitive to the absolute increase in detour distance than to the relative increase compared to the straight route. The qualitative and quantitative results agree with a simple rule: do not use the detour unless the energy gain from extra food outweighs the energy cost of extra travel. These results suggest that members of this group integrate information on spatial location, reward, and perhaps potential food competition in their choice of multi-site foraging routes, with important implications for social foraging.},
	number = {3},
	journal = {Animal Cognition},
	author = {C Janson},
	year = {2007},
	pages = {341--356}
},

@article{kim_2008,
	title = {Prefrontal coding of temporally discounted values during intertemporal choice},
	volume = {59},
	url = {http://dx.doi.org/10.1016/j.neuron.2008.05.010},
	doi = {10.1016/j.neuron.2008.05.010},
	abstract = {Reward from a particular action is seldom immediate, and the influence of such delayed outcome on choice decreases with delay. It has been postulated that when faced with immediate and delayed rewards, decision makers choose the option with maximum temporally discounted value. We examined the preference of monkeys for delayed reward in an intertemporal choice task and the neural basis for real-time computation of temporally discounted values in the dorsolateral prefrontal cortex. During this task, the locations of the targets associated with small or large rewards and their corresponding delays were randomly varied. We found that prefrontal neurons often encoded the temporally discounted value of reward expected from a particular option. Furthermore, activity tended to increase when discounted values for targets were presented in the neuron's preferred direction, suggesting that activity related to temporally discounted values in the prefrontal cortex might determine the animal's behavior during intertemporal choice.},
	number = {1},
	journal = {Neuron},
	author = {S. Kim and J. Hwang and D. Lee},
	year = {2008},
	pages = {161--172}
},

 @article{buckingham_2007,
  title={Shoaling decisions in female swordtails: how do fish gauge group size?},
  volume={144},
  DOI={10.1163/156853907782418196},
  abstract={Little is known about the mechanisms individuals might use to compare group sizes when making decisions about group membership. One possibility is that animals use ratio to determine differences in group sizes. Weber's Law states that the ease of any numerical comparison is based on the ratio between the stimuli compared; as the ratio becomes smaller the comparison becomes more difficult. We set out to test this prediction by offering female green swordtails, Xiphophorus helleri, dichotomous choices between different shoal sizes, varying both in ratios and absolute numbers of fish. Swordtails attended to the ratio of group size between stimulus shoals, rather than the numerical difference between shoals, when making shoaling decisions. Where group size ratio was 2:1, subjects showed a significant preference for the larger shoal, independent of the numerical difference between the shoals. When the ratio was 1.5:1, subjects showed no preference. The ratio between group sizes may, thus, be an important factor in shoaling decisions. More broadly, ratio could prove to be a widespread mechanism for animals to make numerical comparisons in group assessments.},
  number={11},
  journal={Behaviour},
  author={Buckingham, Jessica N. and Wong, Bob B. M. and Rosenthal, Gil G.},
  year={2007},
  pages={1333--1346}
},


 @article{gomez_2011,
  title={Can angelfish (\emph{{P}terophyllum scalare}) count? {D}iscrimination between different shoal sizes follows {W}eber's law},
  volume={14},
  DOI={10.1007/s10071-010-0337-6},
  abstract={The ability to discriminate between larger and smaller quantities has been demonstrated in several mammalian and avian species suggesting the possibility of evolutionary conservation of this characteristic. Preference for the larger of two groups has also been shown in fish species, although this ability has rarely been systematically studied in lower order vertebrates, and thus the mechanisms of such ability are not understood. Here, we exploit the tendency of angelfish to seek protection in an unfamiliar environment by joining a group of conspecifics, a behaviour called shoaling. Test fish were given a simultaneous choice between shoals varying both in terms of numerical ratios and absolute numbers of fish. Our results provide evidence for quantity discrimination in angelfish. In general, experimental subjects chose the larger of two shoals. Furthermore, in agreement with Weber’s law, which holds that discrimination between two quantities depends on their ratio, the discrimination between shoals of different quantities of fish was more difficult when the shoal sizes became more similar. The limit of discrimination ratio was found to be below 2:1. Briefly, angelfish are able to discriminate between different quantities of conspecifics subject to a ratio limit, a finding that implies a fitness component in this behaviour similar to what has been demonstrated in higher order vertebrates.},
  number={1},
  journal={Animal Cognition},
  author={G\'{o}mez-Laplaza, Luis and Gerlai, Robert},
  year={2011},
  pages={1--9}
},

 @article{bakeman_2005,
  title={Recommended effect size statistics for repeated measures designs},
  volume={37},
  DOI={10.3758/BF03192707},
  abstract={Investigators, who are increasingly implored to present and discuss effect size statistics, might comply more often if they understood more clearly what is required. When investigators wish to report effect sizes derived from analyses of variance that include repeated measures, past advice has been problematic. Only recently has a generally useful effect size statistic been proposed for such designs: generalized eta squared (η; Olejnik & Algina, 2003). Here, we present this method, explain that η is preferred to eta squared and partial eta squared because it provides comparability across between-subjects and within-subjects designs, show that it can easily be computed from information provided by standard statistical packages, and recommend that investigators provide it routinely in their research reports when appropriate.},
  number={3},
  journal={Behavior Research Methods},
  author={Bakeman, Roger},
  year={2005},
  pages={379--384}
}

@misc{r_manual_2010,
	address = {Vienna},
	title = {R: A Language and Environment for Statistical Computing},
	isbn = {3-900051-07-0},
	note = {\url{http://www.R-project.org}},
	publisher = {R Foundation for Statistical Computing},
	author = {{R Development Core Team}},
	year = {2011},
	keywords = {R statistical software}
},

@book{sarkar_2008,
    address = {New York},
    title = {Lattice: Multivariate Data Visualization with {R}},
    author = {Deepayan Sarkar},
    publisher = {Springer},
    year = {2008},
}

﻿ @book{epicalc_2010,
  title={epicalc: Epidemiological calculator},
  url={http://CRAN.R-project.org/package=epicalc},
  note={R package version 2.12.2.0},
  author={Chongsuvivatwong, Virasakdi},
  year={2011}
}

 @book{hmisc_2010,
  title={Hmisc: Harrell Miscellaneous},
  url={http://CRAN.R-project.org/package=Hmisc},
  note={R package version 3.8-3},
  author={Harrell, F E},
  year={2010}
}

 @book{psych_2010,
  place={Northwestern University, Evanston, Illinois},
  title={psych: Procedures for Psychological, Psychometric, and Personality Research},
  url={http://personality-project.org/r/psych.manual.pdf},
  note={R package version 1.0-93},
  author={Revelle, William},
  year={2010}
}

 @article{al-imari_2008,
  title={Sight of conspecifics as reward in associative learning in zebrafish (\emph{{D}anio rerio})},
  volume={189},
  DOI={10.1016/j.bbr.2007.12.007},
  abstract={Large amount of genetic information has been accumulated for zebrafish. Learning and memory have also been investigated with zebrafish but the number of learning paradigms is limited. Here we present a simple associative task and investigate a novel reinforcer. We show that visual access to a group of conspecifics has rewarding properties and that this reinforcer can support associative learning in zebrafish. We discuss the advantages of this rewarding stimulus and make recommendations for its use in high throughput behavioral screens.},
  number={1},
  journal={Behavioural Brain Research},
  author={Al-Imari, Lina and Gerlai, Robert},
  year={2008},
  pages={216--219}
}

 @article{griffiths_2003,
  title={Learned recognition of conspecifics by fishes},
  volume={4},
  DOI={10.1046/j.1467-2979.2003.00129.x},
  abstract={The study of partner-choice decisions of individual fish is a good way in which insights into patterns of school structure or territorial assemblages can be gained. Most initial work has focused on the recognition abilities and association patterns of fish in situations where the potential for adaptive costs and benefits is great, such as in the contexts of foraging or antipredator behaviour. However, the benefits of condition-independent recognition and kin recognition may also have profound effects on patterns of movement and dispersal. Information regarding group membership may be especially important in understanding the spatial position of fish in threatened stocks, and may therefore have implications for fisheries management policies. Future work may therefore benefit from an exploration of the ecological contexts in which learned recognition is important in natural streams and rivers.},
  number={3},
  journal={Fish and Fisheries},
  author={Griffiths, Sian W},
  year={2003},
  pages={256--268}
}

 @article{magurran_1991,
  title={Variation in schooling and aggression amongst guppy (\emph{{P}oecilia reticulata}) populations in {T}rinidad},
  volume={118},
  DOI={10.1163/156853991X00292},
  abstract={Schooling behaviour is an effective defence against predation but, since it depends on coordinated behaviour, it may restrict individual competition for limited resources. We tested the hypothesis that levels of individual aggression will be reduced in fish with a high schooling tendency by comparing the behaviour of guppies, Poecilia reticulata, from eight Trinidad populations. Schooling tendency was assayed in the wild. Fish were then transferred to the laboratory where aggression was measured when groups of eight males foraged on a small, but profitable, food patch. An inverse relationship between schooling tendency and intensity of aggression emerged. Guppies from populations without fish predators displayed a wide range of aggressive behaviours including active patch defence by the most dominant individual. Conversely, populations experiencing high predation, and with well-developed schooling behaviour, showed little aggression. Female guppies (three population tested) also varied in level of aggression and aggression was present in laboratory-bred as well as wild-caught fish. Individual aggression increased with group size but was independent of tank size. These results point towards a trade-off between antipredator behaviour and resource defence and confirm that schooling has associated costs as well as benefits.},
  number={3-4},
  journal={Behaviour},
  author={Magurran, A E and Seghers, B H},
  year={1991},
  pages={214--234}
}

 @book{magurran_2005,
  address={Oxford},
  title={Evolutionary Ecology: The {T}rinidadian Guppy},
  ISBN={9780198527862},
  publisher={Oxford University Press},
  author={Magurran, Anne E.},
  year={2005}
}

 @article{trouilloud_2004,
  title={Head raising during foraging and pausing during intermittent locomotion as components of antipredator vigilance in chipmunks},
  volume={67},
  DOI={10.1016/j.anbehav.2003.04.013},
  abstract={Although many studies of vigilance examine head raising in foraging, grooming or resting animals, pauses during intermittent locomotion are rarely considered from the perspective of vigilance, and no studies have compared head raising and pausing in the same system. We videotaped central place foraging chipmunks, Tamias striatus, as they approached a patch, collected sunflower seeds, and left to return to their burrows. There was a strong similarity between head raising during foraging and pausing during intermittent locomotion. Chipmunks paused more frequently when moving towards the patch than when leaving the patch. Chipmunks in the patch raised their heads at an intermediate rate, which tended to decrease with time in the patch. Pauses and the duration of motionless periods during head raises were very short (~0.4 s), and their frequency distributions were similar. Animals remained motionless during 22% of the time spent approaching the patch, 14% of the time spent in the patch and 7% of the time spent leaving the patch. Rates of pausing and head raising generally decreased with short-term familiarity (number of trips to the patch) and with long-term familiarity (proximity of the patch to the burrow). Trials with higher pause rates when approaching the patch had higher head-raising rates in the patch. Whether the focal individual was solitary, dominant or subordinate in a dyad, or competing with multiple chipmunks in the patch had no effect on pausing or head raising. In a separate experiment, exposure to a model hawk increased pause and head-raising rates. We conclude that head raising during foraging and pausing during locomotion serve a similar vigilance function, that this vigilance is directed towards detection of predators rather than conspecifics, and that time allocated to vigilance is sufficient to significantly reduce foraging rates and affect many space use and foraging decisions.},
  number={4},
  journal={Animal Behaviour},
  author={Trouilloud, Wiline and Delisle, Aur\'{e}lie and Kramer, Donald L.},
  year={2004},
  pages={789--797}
}

 @article{green_2004,
  title={Discounting of delayed food rewards in pigeons and rats: is there a magnitude effect?},
  volume={81},
  DOI={10.1901/jeab.2004.81-39},
  abstractNote={Temporal discounting refers to the decrease in the present, subjective value of a reward as the time to its receipt increases. Results from humans have shown that a hyperbola-like function describes the form of the discounting function when choices involve hypothetical monetary rewards. In addition, magnitude effects have been reported in which smaller reward amounts are discounted more steeply than larger amounts. The present research examines the cross-species generality of these findings using real rewards, namely food pellets, with both pigeons and rats. As with humans, an adjusting amount procedure was used to estimate the amount of immediate reward judged equal in value to a delayed reward. Different amounts of delayed food rewards (ranging from 5 to 32 pellets in pigeons and from 5 to 20 pellets in rats) were studied at delays varying from 1 s to 32 s. A simple hyperbola, similar to the hyperbola-like mathematical function that describes the discounting of hypothetical monetary rewards in humans, described the discounting of food rewards in both pigeons and rats. These results extend the generality of the mathematical model of discounting. Rates of discounting delayed food rewards were higher for pigeons than for rats. Unlike humans, however, neither pigeons nor rats showed a reliable magnitude effect: Rate of discounting did not vary systematically as a function of the amount of the delayed reward.},
  number={1},
  journal={Journal of the Experimental Analysis of Behavior},
  author={Green, L and Myerson, J and Holt, D D and Slevin, J R and Estle, S J},
  year={2004},
  pages={39--50}
}

 @article{hogan_1970,
  title={Display and food as reinforcers in the {S}iamese fighting fish (\emph{{B}etta splendens})},
  volume={70},
  DOI={10.1037/h0028737},
  abstractNote={13 male Bettas were required to swim through a small tunnel and exposed to fixed ratio (FR) schedules of reinforcement, FR1-FR6. In Exp. I the opportunity to show aggressive display at their mirror image was used as the reinforcement. As the FR increased, the total number of responses/12-hr session remained almost constant, while the number of reinforcements/session decreased. In Exp. II food was used as the reinforcement. As the FR increased, the total number of responses/12-hr session increased, while the number of reinforcements remained almost constant. In 2 other experiments the duration of display reinforcement was varied 5-40 sec. The 5-sec time interval was less effective than the other intervals, but differences were not statistically significant. Results support the conclusion that the 2 reinforcers depend on different mechanisms for their effects. (PsycINFO Database Record (c) 2006 APA, all rights reserved)},
  number={3},
  journal={Journal of Comparative and Physiological Psychology},
  author={Hogan, Jerry A. and Kleist, Suzanne and Hutchings, C.S.},
  year={1970},
  pages={351--357}
}

 @article{leland_2002,
  title={Similarity judgments and anomalies in intertemporal choice},
  volume={40},
  DOI={10.1093/ei/40.4.574},
  abstractNote={This article demonstrates that choices based on similarity judgments will exhibit not only common ratio and reflection effects under uncertainty but also common difference and reflection effects in intertemporal contexts.},
  number={4},
  journal={Economic Inquiry},
  author={Leland, J W},
  year={2002},
  pages={574--581}
}

 @article{rubinstein_2003,
  title={``Economics and psychology''? {T}he case of hyperbolic discounting},
  volume={44},
  DOI={10.1111/1468-2354.t01-1-00106},
  abstractNote={The article questions the methodology of "economics and psychology" in its focus on the case of hyperbolic discounting. Using some experimental results, I argue that the same type of evidence, which rejects the standard constant discount utility functions, can just as easily reject hyperbolic discounting as well. Furthermore, a decision-making procedure based on similarity relations better explains the observations and is more intuitive. The article concludes that combining "economics and psychology" requires opening the black box of decision makers instead of modifying functional forms.},
  number={4},
  journal={International Economic Review},
  author={Rubinstein, A},
  year={2003},
  pages={1207--1216}
}

 @article{scholten_2010,
  title={The psychology of intertemporal tradeoffs},
  volume={117},
  DOI={10.1037/a0019619},
  abstractNote={It is commonly assumed that people make intertemporal choices by “discounting” the value of delayed outcomes, assigning discounted values independently to all options, and comparing the discounted values. We identify a class of anomalies to this assumption of alternative-based discounting, which collectively shows that options are not treated independently but rather comparatively: The time difference, or interval, between the options sometimes counts more and sometimes counts less if it is taken as a whole than if it is divided into shorter subintervals (superadditivity and subadditivity, respectively), and whether the interval counts more or less depends on the money difference, or compensation, involved (inseparability). We develop a model that replaces alternative-based discounting with attribute-based tradeoffs. In our model, people make intertemporal choices by weighing how much more they will receive or pay if they wait longer against how much longer the wait will be, or, conversely, how much less they will receive or pay if they do not wait longer against how much shorter the wait will be. This model, called the tradeoff model, accommodates, in a psychologically plausible way, all anomalies that the discounting approach can and cannot address. (PsycINFO Database Record (c) 2010 APA, all rights reserved)},
  number={3},
  journal={Psychological Review},
  author={Scholten, Marc and Read, Daniel},
  year={2010},
  pages={925--944}
}

 @article{shapiro_2009,
  title={Parameters of rewards on choice behavior in {S}iamese fighting fish (\emph{{Betta} splendens})},
  volume={82},
  DOI={10.1016/j.beproc.2009.03.007},
  abstractNote={Five experiments were conducted with Siamese fighting fish (Betta splendens) to investigate how choices in a T-maze were affected by parameters of a social reward (aggression display to another male): presence or absence, amount, delay and distance traveled. Bettas showed a preference for the side associated with the presence of another male rather than the side associated with nothing (Exp 1), a greater length of time of the reward (Exp 2) and shorter delay (Exp 3). The animals were indifferent when one side offered a longer delay to a longer reward time compared with a shorter delay to a shorter reward time (Exp 4). What was most surprising, however, was that fish preferred to choose the side that was associated with swimming a greater distance to reach an opponent male (Exp 5). These experiments demonstrate that, while some parameters of a visual reward affect behavior in predicable ways (greater amount, shorter delay), the complex motivations underlying inter-male aggression can produce what appear to be paradoxical results.},
  number={1},
  journal={Behavioural Processes},
  author={Shapiro, Martin S. and Jensen, Ashley L.},
  year={2009},
  pages={30--38}
}

 @article{shapiro_2008,
  title={Simultaneous and sequential choice as a function of reward delay and magnitude: normative, descriptive and process-based models tested in the {E}uropean starling (\emph{{S}turnus vulgaris})},
  volume={34},
  DOI={10.1037/0097-7403.34.1.75},
  abstractNote={The authors analyze prevalent theoretical and empirical quantitative models of choice using data from European starlings (Sturnus vulgaris). The different models originate from diverse lines of thinking, including optimal foraging theory, descriptive behavioral analysis, and temporal discounting. The authors also investigate the Sequential Choice Model (SCM) that predicts choice between simultaneous alternatives as a function of behavior in sequential encounters. SCM assumes that simultaneous encounters are rare in nature, where animals often exploit or dismiss single opportunities. Mechanisms of choice adapted for sequential encounters may be evolutionarily stable even if they impose a cost in the rarer simultaneous cases. The best predictive power is achieved by the SCM and by hyperbolic discounting with value (or attractiveness) of each option proportional to reward amount and inversely proportional to the sum of delay to reward plus delay to respond. Choice probability matched the ratio of each option's value to the sum of values of all available options. The good fit of SCM supports the view that choice is driven by mechanisms adapted to sequential, rather than simultaneous encounters with feeding opportunities.},
  number={1},
  journal={Journal of Experimental Psychology: Animal Behavior Processes},
  author={Shapiro, M S and Siller, S and Kacelnik, A},
  year={2008},
  pages={75--93}
}

 @article{niv_2006,
  title={A normative perspective on motivation},
  volume={10},
  DOI={10.1016/j.tics.2006.06.010},
  abstractNote={Understanding the effects of motivation on instrumental action selection, and specifically on its two main forms, goal-directed and habitual control, is fundamental to the study of decision making. Motivational states have been shown to [`]direct' goal-directed behavior rather straightforwardly towards more valuable outcomes. However, how motivational states can influence outcome-insensitive habitual behavior is more mysterious. We adopt a normative perspective, assuming that animals seek to maximize the utilities they achieve, and viewing motivation as a mapping from outcomes to utilities. We suggest that habitual action selection can direct responding properly only in motivational states which pertained during behavioral training. However, in novel states, we propose that outcome-independent, global effects of the utilities can 'energize' habitual actions.},
  number={8},
  journal={Trends in Cognitive Sciences},
  author={Niv, Yael and Joel, Daphna and Dayan, Peter},
  year={2006},
  pages={375--381}
}

 @article{cooper_2000,
  title={Increasing costs of access to resources cause re-scheduling of behaviour in American mink (\emph{{M}ustela vison}): implications for the assessment of behavioural priorities},
  volume={66},
  DOI={10.1016/S0168-1591(99)00069-6},
  abstractNote={Consumer demand studies of animal preference commonly involve the imposition of costs on access to resource compartments rather than direct costs on resource consumption. The aim of this study was to analyse how such increasing access costs alter the scheduling of behaviour, in order to investigate some potential problems with using this technique to measure behavioural priorities.  . We investigated the effect on mink of placing a cost a weighted door on the access to resources. Six mink were individually housed in closed economy test arenas. Each consisted of a home cage containing food, water and a nest box , an empty compartment and six resource compartments with access to a box of hay, a water bath, a raised platform, a wire cylinder, a novel object, and small toys. Door weights were increased from 0 to 1000 g and the minks’ behaviour was recorded on video for 8 h per day. As expected, increasing door weight reduced the number of visits to each compartment but lengthened each visit. Furthermore, as costs on access increased, there were changes in how mink behaved during each visit to resource-compartments. They became increasingly likely to interact with each resource during a visit, and they showed shorter latencies to interact with the resources. The time spent in compartments not interacting with the resources also declined. Overall, these changes in within-visit behaviour meant that the greater the cost on access, the greater the proportion of time spent with a resource devoted to actually interacting with it. Thus, the time spent with a resource over-estimated the actual use of that resource, particularly at lower access costs. These results illustrate the dangers of simply using time spent with a resource as a measure of consumption in studies of behavioural priorities. As a consequence of longer visits and more interaction, the total time spent swimming, manipulating the novel objects and occupying the hay box did not decline with increasing door weight. However, unexpectedly, this compensatory re-scheduling did not occur for all activities, because the time spent occupying the platform, manipulating the toys and the cylinder and the time in the empty compartment declined with higher access costs. This suggests that increasing access costs for unlimited periods of time with resources may, although not strictly valid for the production of demand curves, yield a ranking of behavioural priorities if high enough costs are used. Further research is necessary to see whether the minks’ failure to defend time spent in the platform, manipulating toys and the wire cylinder and in the empty compartment does represent the low priority of these activities. Or whether some other factors, such as constraints on the ability to re-schedule the activities prevent mink from compensating for higher costs on access. q2000 Elsevier Science B.V. All rights
reserved.
Keywords: Motivation; Enrichment; Behavioural needs; Consumer demand; Welfare; Mink},
  number={1-2},
  journal={Applied Animal Behaviour Science},
  author={Cooper, J J and Mason, G J},
  year={2000},
  pages={135--151}
}

 @article{mason_2001,
  title={Frustrations of fur-farmed mink},
  volume={410},
  DOI={10.1038/35065157},
  number={6824},
  journal={Nature},
  author={Mason, G and Cooper, J J and Clarebrough, C},
  year={2001},
  pages={35--36}
}

 @article{dawkins_1990,
  title={From an animal's point of view: motivation, fitness, and animal welfare},
  volume={13},
  abstractNote={Suggests that to study animal welfare empirically, an objective basis is needed for deciding when an animal is suffering. Suffering includes a range of unpleasant emotional states (e.g., fear, pain) that appear to have evolved to avoid danger or restore physiological defects resulting from the natural environment. Suffering occurs when otherwise healthy animals are prepared to pay a price to attain or to escape from a particular situation. Withholding conditions or commodities for which animals show "inelastic demand" (i.e., for which they continue to work despite increasing costs) may cause suffering. In designing animal environments in zoos, farms, and laboratories, priority should be given to features for which animals show inelastic demand. 42 comments and a reply follow. (PsycINFO Database Record (c) 2002 APA, all rights reserved).},
  number={1},
  journal={Behavioral and Brain Sciences},
  author={Dawkins, M S},
  year={1990},
  pages={1--61}
}

 @article{sherwin_1996,
  title={Reorganization of behaviour in laboratory mice, \emph{{M}us musculus}, with varying cost of access to resources},
  volume={51},
  DOI={10.1006/anbe.1996.0110},
  abstractNote={Gaining access to resources can be measured in terms of the time spent with, or the number of visits to, a resource. For some resources, time spent with the resource might be more important, for others the number of visits might be more meaningful. By using traverses of shallow water, the costs of gaining access to food, shelter, a conspecific, increased space, a running wheel, deep sawdust, or enrichments (e.g. balls, a variety of small objects) were increased for laboratory mice. When 30 cm of water was present, the number of visits to each resource decreased to 39–64% of the number recorded when no water was present, but the proportion of time spent with each resource was defended. Increasing the width of water to 120 cm had no further effect on the number of visits or on the proportion of time spent with each resource: thus both the frequency of visits and the proportion of time with each resource were ultimately defended. Possible reasons for this change in behavioural organization, including the importance of patrolling, are discussed. The data support previous findings that laboratory mice are highly motivated to patrol areas made accessible to them, and suggest that care is needed when interpreting what animals perceive as reinforcement during visits to resources. Furthermore, it was shown that for laboratory mice under conditions that penalize initial access only, the time spent with a wide variety of resources was defended more diligently than the number of visits, but the number of visits was rarely allowed to decrease to zero.},
  number={5},
  journal={Animal Behaviour},
  author={Sherwin, C M and Nicol, C J},
  year={1996},
  pages={1087--1093}
}

 @article{matthews_1994,
  title={Environmental requirements of pigs measured by behavioural demand functions},
  volume={47},
  DOI={10.1006/anbe.1994.1096},
  abstractNote={Individual domestic pigs, Sus scrofa, were given the opportunity in daily test sessions to work on fixed ratio (FR) schedules of reinforcement for access to one of three different commodities (food, contact with a partner animal, and a stimulus change called 'door opening'). The amount of work required for access to each reinforcer was varied systematically by changing the size of the FR schedule (FR 1, 2, 5, 10, 15, 20 and 30). Demand curves, analogous to those used in economics, were derived for each commodity. The slopes of these curves were shallowest (inelastic demand) for food, an apparently essential item, and were steepest (more elastic demand) for door opening, an apparently less essential item. Demand functions could be generated for a range of different stimuli and demand elasticity appeared to provide a useful quantitative index of the relative importance of different environmental features to pigs.},
  number={3},
  journal={Animal Behaviour},
  author={Matthews, L R and Ladewig, Ja},
  year={1994},
  pages={713--719}
}

 @article{lea_1978,
  title={The psychology and economics of demand},
  volume={85},
  DOI={10.1037/0033-2909.85.3.441},
  abstractNote={Notes that the demand curve used in economics may be analogous to the function relating the number of reinforcements obtained on a schedule of reinforcement to some parameter of the schedule. The limits of this analogy are explored, and literature from operant laboratory research, consumer research, and econometrics is surveyed, showing that both similarities and differences exist between supposedly analogous economic and psychological data. It is felt that the empirical similarities are sufficient to suggest that the theoretical differences between reinforcement theory and demand theory (which is based on rationality) may be less important than they appear. Situations intermediate between the laboratory and the economy are examined, and no discontinuity of behavior is found. (4 p ref) (PsycINFO Database Record (c) 2002 APA, all rights reserved).},
  number={3},
  journal={Psychological Bulletin},
  author={Lea, S},
  year={1978},
  pages={441--466}
}

 @inbook{stevens_2011,
  address={Cambridge, MA},
  series={Strüngmann Forum Report},
  title={Mechanisms for decisions about the future},
  booktitle={Animal Thinking: Contemporary Issues in Comparative Cognition},
  publisher={MIT Press},
  author={Stevens, Jeffrey R},
  editor={Menzel, R and Fischer, J},
  year={2011},
  pages={in press},
  collection={Strüngmann Forum Report}
}

 @article{cheng_2002,
  title={Self-control in honeybees},
  volume={9},
  abstractNote={Self-control means choosing a large delayed reward over a small immediate reward; impulsiveness is its opposite. The metabolic hypothesis states that the amount of self-control across species correlates negatively with metabolic rate. Foraging honeybees have high metabolic rates; the metabolic hypothesis would predict little self-control in bees. But foraging bees work for the long-term good of their hive, conditions that seem to require self-control. In 3 experiments, we gave bees the choice between (1) a sweeter delayed reward and a less sweet immediate reward and (2) a large delayed reward and a small immediate reward. Bees showed much self-control, inconsistent with the metabolic hypothesis. (PsycINFO Database Record (c) 2002 APA, all rights reserved).},
  number={2},
  journal={Psychonomic Bulletin and Review},
  author={Cheng, K and Penea, J and Porter, M A and Irwin, J D},
  year={2002},
  pages={259-263}
}

 @article{tobin_1996,
 title={Self-control in the monkey Macaca fascicularis},
 volume={24},
 abstractNote={Tested 2 macaques’ self-control (choice of a longer, more delayed reinforcer over a shorter, less delayed reinforcer). In Exp 1, Ss exhibited significant self-control in a procedure in which reinforcer amounts and delays were held constant throughout a condition. In Exp 2, Ss exhibited significantly greater sensitivity to variation in reinforcer amount than to variation in reinforcer delay in a procedure in which the reinforcer delay associated with the self-control alternative was adjusted until each S was indifferent between the 2 alternatives. Results indicate that, in laboratory paradigms in which humans show self-control and pigeons and rats show impulsiveness, these macaques show self-control. Results are consistent with the hypothesis that species differences in self-control are related to the ratio of brain size to body weight (a possible indicator of general cognitive ability) or to shared phylogeny. (PsycINFO Database Record (c) 2000 APA, all rights reserved).},
 number={2},
 journal={Animal Learning and Behavior},
 author={Tobin, H and Logue, A W and Chelonis, J J and Ackerman, K T},
 year={1996},
 pages={168-174}
}






