Skip to content

Research at St Andrews

Disentangling great apes’ decoy-effect bias in a food choice task

Research output: Contribution to journalArticle


Alejandro Sánchez-Amaro, Nazli Altinok, Christophe Heintz, Josep Call

School/Research organisations


The decoy effect is a violation of rationality that occurs when the relative preference between two target options changes with the addition of a third option, called the decoy, that is no better than the target options but worse than one of the options on one attribute. The presence of the decoy increases the chance that the option that dominates it on this attribute is chosen over the other target option. The current study tested decoy effects with great apes’ food preferences. We presented apes with two target items, grape and banana, and a third item, the decoy, which was either a smaller grape or a smaller piece of banana. We found that apes’ decisions were not influenced by the presence of a decoy. In general, apes did not increase their choices in favor of the target item that dominated the decoy. This would indicate that great apes are not vulnerable to the cognitive biases that cause decoy effects in humans, at least in cases where choice is between two different types of food. We discuss what can be concluded about the psychological causes of human irrational choices and their evolutionary origin.


Original languageEnglish
Pages (from-to)213-222
Number of pages10
JournalAnimal Behavior and Cognition
Issue number3
Publication statusPublished - 1 Aug 2019

    Research areas

  • Decoy-effect, Rationality, Great apes, Food preferences

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Revisiting the possibility of reciprocal help in non-human primates

    Schweinfurth, M. K. & Call, J., Sep 2019, In : Neuroscience and Biobehavioral Reviews. 104, p. 73-86 14 p.

    Research output: Contribution to journalReview article

  2. Innovative problem solving in great apes: the role of visual feedback in the floating peanut task

    Ebel, S. J., Schmelz, M., Herrmann, E. & Call, J., Sep 2019, In : Animal Cognition. 22, 5, p. 791-805 15 p.

    Research output: Contribution to journalArticle

  3. Bargaining in chimpanzees (Pan troglodytes): the effect of cost, amount of gift, reciprocity and communication

    Bueno-Guerra, N., Voelter, C. J., de las Heras, Á., Colell, M. & Call, J., 27 Jun 2019, In : Journal of Comparative Psychology. Online First

    Research output: Contribution to journalArticle

  4. Theory of mind in animals: current and future directions

    Krupenye, C. & Call, J., 17 May 2019, In : Wiley Interdisciplinary Reviews: Cognitive Science. Early View, e1503.

    Research output: Contribution to journalReview article

Related by journal

  1. Remembering past exchanges: apes fail to use social cues

    Lewis, A., Bernsten, D. & Call, J., 1 Feb 2018, In : Animal Behavior and Cognition. 5, 1, p. 19-40

    Research output: Contribution to journalArticle

  2. Chickadee songs provide hidden clues to singers’ locations

    Mercado, E., Wisniewski, M. G., Mcintosh, B., Guillette, L., Hahn, A. H. & Sturdy, C., 1 Aug 2017, In : Animal Behavior and Cognition. 4, 3, p. 301-313

    Research output: Contribution to journalArticle

ID: 259651502