Arbitrary Conventions

Chimpanzees learn meaning of arbitrary objects by watching others

Chimpanzees watch as Georgia deposits an orange token into the bucket receptacle. All chimps in this group copied Georgia’s actions.

Some human cultural practices are entirely arbitrary, that is, they are not based on the logic of efficiency, such as bowing in some cultures and shaking hands in others. In our close relatives such cultural differences have been suggested but never proven.

To see if and how arbitrary conventions develop among chimpanzees, this study investigated whether the apes could learn an arbitrary sequence of actions, performed to receive a food reward, by watching one of their trained peers deposit tokens in one of two different containers. It was found that chimpanzees acquired the convention used by their companions, and this developed into a local tradition.

The behavior likely spread because new practitioners recognized the significance of the action sequence performed by the high-ranking female model in each group and thus copied what she did. In each community, members know the local meaning of an object, reacting to it in a unique but predictable manner, similar to behaviors seen in human social groups and among wild chimpanzees. By understanding how arbitrary practices originate in chimpanzees, we may gain better understanding of human practices and the way human culture and behavior has evolved.