This is the first time that such conventions have been studied experimentally in an animal species., note the researchers associated with the Rousset Primate Station of the French Center for Scientific Studies.
The principle of conventions is not specific to the human species and has already been observed in certain monkeys, in particular during delousing sessions. But these are behaviors that appear spontaneously within a group, without human intervention.
About twenty guinea baboons, raised at the Primate Station, were offered several images that they could choose by touching a touch screen.
Each image, shown randomly to two monkeys in an enclosure, included two squares of two different colors (therefore two possible answers). If both individuals selected the same color, they received a reward: wheat.
Over the course of the tests – tens of thousands recorded on the computer – the monkeys quickly developed a hierarchical organization of images by agreeing on the same color: they almost always took the pink square when presented with the light blue square, or the yellow square next to a pink square.
Each individual first had the opportunity to see what was happening on the other’s screen. But in the next sequence, visual access to the (changing) partner was closed, and the group’s performance
did not move, explains Anthony Formaux, from the Cognitive Psychology Laboratory (Aix-Marseille University / CNRS) to AFP.
It surprised us that they keep choosing the same image without resorting to imitation., comments this doctoral student, main author of the study published in the journal Philosophical Transactions of the Royal Society B (New window) (in English).
Simple sensitivity to colors more prominent than others? Not only, since the same manipulation was offered to them with black and white drawings, and the group continued to organize themselves around the same motif.
This behavior respects the three main characteristics of a convention, underlines the CNRS in a press release: efficiency (the reward benefits everyone), stability (the rule works so it does not change), with arbitrariness as a prerequisite ( other solutions are possible).
In humans, social conventions, such as kissing or shaking hands to greet each other, also facilitate
the resolution of coordination problems encountered by the group, Anthony Formaux analysis. According to him,
language is a huge convention, since originally individuals had to agree on words.
How to interpret such an organization without recourse to language?
It is assumed that the baboons knew that the group had come to an agreement, but it is not clear how, he replies.