We do not behave in the same way when making so-called "risky" decisions depending on whether we base them on clearly defined and accessible probabilities of the situation, or on our past experiences facing uncertainty, without prior knowledge of the consequences of the decision. This process, known as the Description-Experience Gap, has been extensively studied in humans but remains relatively unexplored in non-human primates. Here, Anthony Roig, as part of a postdoctoral study conducted in collaboration with Elsa Addessi of the University of Rome and Helene Meunier of the LNCA & the Primate Centre of the University of Strasbourg, studied the behaviour of 15 brown capuchin monkeys (Sapajus spp.) in such situations. This species is known for its cognitive flexibility, its ability to adapt to uncertain environments, and its propensity for risk is particularly well documented.
The task involves a binary choice between a "safe" option that always provides a food reward and a "risky" option that offers four times as many rewards but with four times less probability of obtaining them. Two experimental conditions are proposed: a) description: the probabilities are clearly presented visually, with a choice among four containers, only one of which contains a reward (Fig. a); b) experience: a single container of four rewards only 25% of the time (Fig. b).
Although cautious in both conditions, Capuchins chose the risky option more often in the description condition than in the experiment condition. Visual access to probabilities thus appears to promote a more risk prone attitude than direct experience. Furthermore, capuchins with more experience facing risk exhibit more uniform decision-making patterns between the two conditions, while those with less experience tend to take more risks in the experiment condition.
Thus, the attitude toward risk depends on the method of acquiring probabilistic information. Knowing a probability through description and having experienced it do not produce the same decision-making behaviours in capuchins, even when the objective information is identical. These results help clarify the evolutionary mechanisms of decision-making under uncertainty, offering valuable insights into how ecological, demographic, and experiential factors jointly shape decision-making in primates.
