{"id":203327,"date":"2026-06-16T15:43:30","date_gmt":"2026-06-16T13:43:30","guid":{"rendered":"https:\/\/www.bordeaux-neurocampus.fr\/?p=203327"},"modified":"2026-06-16T16:07:17","modified_gmt":"2026-06-16T14:07:17","slug":"humans-and-rats-the-same-cognitive-biases-when-evaluating-rewards","status":"publish","type":"post","link":"https:\/\/www.bordeaux-neurocampus.fr\/en\/humans-and-rats-the-same-cognitive-biases-when-evaluating-rewards\/","title":{"rendered":"Humans and Rats: The Same Cognitive Biases When Evaluating Rewards"},"content":{"rendered":"
\"\"<\/a>
Shauna Parkes & Stefano Palminteri via Biorender<\/figcaption><\/figure>\n

Imagine choosing between two dishes at a restaurant: one seemed excellent during a mediocre meal, while the other was disappointing during an outstanding dining experience. Even if both dishes are objectively of similar quality, people tend to prefer the first, because it was the best option within its original context. This tendency reflects a well-known cognitive bias in which the value of an experience is encoded relative to the environment in which it was learned, rather than in absolute terms.<\/strong><\/p>\n

A recent study published in Nature Communications<\/em> led by Shauna Parkes (INCIA, DR CNRS) and Lachlan Ferguson (former INCIA postdoctoral researcher, now at UNSW Sydney), in collaboration with Stefano Palminteri (ENS Paris, DR INSERM), Magdalena Soukupova (ENS Paris), and S\u00e9bastien Bouret (ICM Paris, DR CNRS), investigated whether this \u201crelative value\u201d bias is unique to humans or shared across species.<\/p>\n

\n
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Rats and humans were trained on the same decision-making task, in which they had to choose between fixed pairs of visual stimuli (A-B and C-D), each associated with a specific reward probability (0-100%). They were then presented with new choices, including a direct comparison between options B and C. Although B had a higher reward probability than C, both species consistently preferred C. This preference reflects a contextual bias: C had previously been the \u201cbest\u201d option in its pair (C > D), whereas B had been the \u201cworst\u201d option (B < A).<\/figcaption><\/figure>\n

Using closely matched reinforcement-learning tasks in humans and rats, participants learned through trial and error which options were more likely to be rewarded (monetary rewards for humans and food rewards for rats). The options were presented in \u201crich\u201d and \u201cpoor\u201d contexts with different reward rates, before being recombined in a final test where objective reward probabilities were equivalent.<\/p>\n

The results show a strong convergence between species: both humans and rats consistently overvalue options that were the best within their original context, even when they are objectively no better than alternatives. This bias also leads to suboptimal choices when context-based preferences conflict with actual reward rates.<\/p>\n

Computational modelling further revealed that the same underlying learning mechanism could explain behaviour in both species. A reference-based learning model, in which outcomes are evaluated relative to the average reward in each context, best accounted for the observed choices. While this normalization strategy improves efficiency in processing variable environments, it also produces systematic distortions in value-based decision-making.<\/p>\n

These findings suggest that relative value encoding is an evolutionarily conserved feature of decision-making, shared across humans and rodents, and not a uniquely human cognitive bias. More broadly, this work provides a translational framework for studying how context influences learning and decision-making, with important implications for conditions such as addiction, where these processes may be disrupted.<\/p>\n

Reference<\/h3>\n

Reference-point dependent reinforcement learning in humans and rats.<\/em>
\nLachlan A. Ferguson*, Magdalena Soukupova*, S\u00e9bastien Bouret, Stefano Palminteri# & Shauna L. Parkes#.
\nNature Communications<\/i>
\nhttps:\/\/doi.org\/10.1038\/s41467-026-73623-x<\/a>
\n*These authors contributed equally
\n#These authors jointly supervised this work<\/p>\n

Contact<\/h3>\n

Shauna Parkes<\/strong>
\nDirectrice de recherche CNRS (INCIA)
\nshauna.parkes@u-bordeaux.fr<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Authors include: Lachlan Ferguson and Shauna Parkes (INCIA)<\/p>\n","protected":false},"author":108,"featured_media":203326,"comment_status":"closed","ping_status":"closed","sticky":true,"template":"","format":"standard","meta":{"footnotes":""},"categories":[71],"tags":[],"class_list":["post-203327","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-highlight-en"],"_links":{"self":[{"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/posts\/203327","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/users\/108"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/comments?post=203327"}],"version-history":[{"count":2,"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/posts\/203327\/revisions"}],"predecessor-version":[{"id":203335,"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/posts\/203327\/revisions\/203335"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/media\/203326"}],"wp:attachment":[{"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/media?parent=203327"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/categories?post=203327"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bordeaux-neurocampus.fr\/en\/wp-json\/wp\/v2\/tags?post=203327"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}