University of Tübingen: Monkeys keep reinventing the wheel

A research team from the University of Tübingen has shown that great apes have to learn their behavior patterns anew in every generation
Great apes do not pass their behaviors on to the next generation. They do not copy the knowledge of their fellows, but learn it anew in every generation – in contrast to humans. This is shown by a study by Dr. Alba Motes-Rodrigo and Dr. Claudio Tennie from the working group “Tools and Culture in Early Hominins” at the University of Tübingen. “Monkeys rely on reinventing the proverbial wheel over and over again. The shape of the wheel doesn’t change, ”explains Tennie.

The team from the Department of Ancient Prehistory and Quaternary Ecology looked in all published reports on great apes for statements about locally unique behavior patterns, such as chimpanzees who used leaves as spoons to drink water. These were then systematically checked for accuracy. In this way it was checked indirectly whether great ape cultures are built on the same mechanisms as human cultures. The study was published in the journal Biological Reviews.

In human culture, behaviors are learned by observing and copying one another. This is how valuable knowledge is passed on to the next generation. Behavioral patterns are often slightly modified, because people make mistakes when copying or add aspects themselves. In this way, human culture changes from generation to generation. Alba Motes compares this to the game “Silent Mail”, in which a player whispers a term in his neighbor’s ear. The term is passed on from player to player, which often leads to a different term than the original word due to hearing errors.

When exactly the mechanisms of copying, which underlie human culture, came about is a matter of controversy. One thesis is that the ability to copy behavior goes back millions of years and that great apes also copy one another. Another thesis assumes that great apes and many ancestors of humans do not copy one another.

Alba Motes-Rodrigo and Claudio Tennie used a new approach to find evidence of the process of copying in great apes. They tried to identify behaviors in ape populations that have undergone changes from generation to generation. “If the behavior of the great apes is really based on imitation, as is the case with humans, we would expect that their appearance has changed culturally and that there should therefore now be individual behaviors that are only limited to a population in one place”, explains Motes.

The team therefore looked for regionally unique behavior patterns of great apes, both in all published reports on great apes and in discussions with experts on great apes. Their result: the overwhelming majority of the behavior of great apes is not regionally limited. Out of hundreds of behavioral patterns, only three could not be proven elsewhere.

According to the research team, these results show that the apes’ culture is sustained by different learning mechanisms than human culture. In contrast to humans, apes do not copy each other, but reinvent each of their behavior in each population and in each generation over and over again. “They are simply stimulated to these new inventions by others, without the respective form of behavior being copied. This finding seems surprising, but it is supported by the latest studies in comparative cognitive science, ”says Tennie. In these studies, great apes only copied new behaviors if they had previously been trained to behave in behavior copies by humans.