Probability matching is not the default decision making strategy in human and non-human primates

Probability matching has long been taken as a prime example of irrational behaviour in human decision making; however, its nature and uniqueness in the animal world is still much debated. In this paper we report a set of four preregistered experiments testing adult humans and Guinea baboons on matched probability learning tasks, manipulating task complexity (binary or ternary prediction tasks) and reinforcement procedures (with and without corrective feedback). Our findings suggest that probability matching behaviour within primate species is restricted to humans and the simplest possible binary prediction tasks; utility-maximising is seen in more complex tasks for humans as pattern-search becomes more effortful, and we observe it across the board in baboons, altogether suggesting that it is a cognitively less demanding strategy. These results provide further evidence that neither human nor non-human primates default to probability matching; however, unlike other primates, adult humans probability match when the cost of pattern search is low

Rational After All: Changes in Probability Matching Behaviour Across Time in Humans and Monkeys

Probability matching—where subjects given probabilistic in-put respond in a way that is proportional to those input probabilities—has long been thought to be characteristic of primate performance in probability learning tasks in a variety of contexts, from decision making to the learning of linguistic variation in humans. However, such behaviour is puzzling because it is not optimal in a decision theoretic sense; the optimal strategy is to always select the alternative with the highest positive-outcome probability, known as maximising(in decision making) or regularising (in linguistic tasks). While the tendency to probability match seems to depend somewhat on the participants and the task (i.e., infants are less likely to probability match than adults, monkeys probability matchless than humans, and probability matching is less likely in linguistic tasks), existing studies suffer from a range of deficiencies which make it difficult to robustly assess these differences. In this project we present a series of experiments which systematically test the development of probability matching behaviour over time in simple decision making tasks, across species (humans and Guinea baboons), task complexity, and task domain (linguistic vs non-linguistic)

More Accurate Size Contrast Judgments in the Ebbinghaus Illusion by a Remote Culture

International audienceThe Ebbinghaus (Titchener) illusion was examined in a remote culture (Himba) with no words for geometric shapes. The illusion was experienced less strongly by Himba compared with English participants, leading to more accurate size contrast judgments in the Himba. The study included two conditions of inducing stimuli. The illusion was weaker when the inducing stimuli were dissimilar (diamonds) to the target (circle) compared with when they were similar (circles). However, the illusion was weakened to the same extent in both cultures. It is argued that the more accurate size judgments of the Himba derive from their tendency to prioritize the analysis of local details in visual processing of multiple objects, and not from their impoverished naming

Detecting human and non-human vocal productions in large scale audio recordings

We propose an automatic data processing pipeline to extract vocal productions from large-scale natural audio recordings. Through a series of computational steps (windowing, creation of a noise class, data augmentation, re-sampling, transfer learning, Bayesian optimisation), it automatically trains a neural network for detecting various types of natural vocal productions in a noisy data stream without requiring a large sample of labeled data. We test it on two different data sets, one from a group of Guinea baboons recorded from a primate research center and one from human babies recorded at home. The pipeline trains a model on 72 and 77 minutes of labeled audio recordings, with an accuracy of 94.58% and 99.76%. It is then used to process 443 and 174 hours of natural continuous recordings and it creates two new databases of 38.8 and 35.2 hours, respectively. We discuss the strengths and limitations of this approach that can be applied to any massive audio recording

Une nouvelle procédure d’expérimentation comportementale à l’interface entre les approches « Naturalistes » et « Généralistes » de la cognition du primate A new behavioral test procedure at the interface between “Naturalist” and “Generalist” approaches of primate cognition

Le domaine d’étude de la cognition du primate est caractérisé par deux approches distinctes. L’approche Naturaliste consiste à s’intéresser aux comportements naturels, et à tenter de comprendre les facteurs et pressions sélectives qui ont permis l’émergence de ces fonctions au cours de la phylogenèse. L’approche Généraliste postule qu’il existe des traits cognitifs communs entre l’humain et l’animal, et cherche à identifier ces traits dans une recherche de laboratoire. Dans cet article, je présente une nouvelle méthode de recherche favorable à un interfaçage entre ces deux approches. La démarche consiste à installer un laboratoire en périphérie des enclos d’élevage, et à permettre aux sujets d’interagir librement avec les stations expérimentales, alors qu’ils sont maintenus dans leur groupe social. Cet article présente une synthèse des principaux résultats que nous avons obtenus avec cette approche, et les illustre, en en soulignant les avantages de notre approche par rapport aux approches plus traditionnelles de laboratoire.<br>The study of primate cognition may adhere to two different paradigms. The first one is referred to as the Naturalist approach. Investigators in that field attempt to characterize natural behaviors, and to identify the various factors accounting for their evolution in nature.   The second one is referred to as the Generalist approach. Generalist researchers attempt to identify cognitive processes shared by animals and humans. While Naturalist researchers prefer natural or semi-natural conditions for their science, the context favored by the Generalist researchers is the laboratory allowing the test of isolated primates. In that paper, I present a novel experimental protocol favoring an interface between the Naturalist and Generalist approaches. The general idea of this protocol is to present a laboratory nearby an enclosure where monkeys live in a semi-natural context. The test systems installed within the laboratory are opened and freely accessible from the enclosure. The monkeys (baboons in our research) can voluntarily enter the test booth to participate to the research. This protocol has been fully developed, installed and validated in my laboratory during the last 3 years, and I present here the main results collected during that period. I (1) demonstrate that this approach allows the test of a large number of participants which participate to the research at a high frequency, (2) identify the main factors (age, day time, reinforcement rate, etc..) that affect their behavior in the tasks, (3) illustrate the effect of the test systems on the spontaneous behavior of the monkeys, and (4) briefly present two studies that used this method, in order to illustrate its potential for the Generalist and Naturalist research programs

Penser sans langage: approche expérimentale chez le babouin.

International audienceLa recherche sur l'animal est une voie privilégiée pour abor-der la question des relations entre pensée et langage. Le primate non humain, qui n'a pas notre langage, présente une multitude de comportements dont la complexité laisse supposer l'exis-tence d'une cognition de haut niveau. Néanmoins, qu'en est-il réellement ? Dans cette contribution, je présente une série de recherches de psychologie cognitive destinées à comprendre les capacités de perception, d'attention, de mémoire à court et à long terme, ainsi que les aptitudes au raisonnement abstrait du babouin de Guinée (Papio papio). Cet ensemble de don-nées illustre à la fois les limites et les potentialités des systèmes cognitifs sans langage