Chimpanzees show behaviors that led humans to success

Dec. 5 () –

New study suggests key capabilities underlying human language and technological culture may have evolved before humans and apes diverged millions of years ago.

Many human behaviors are more complex than those of other animals and involve the production of elaborate sequences (such as spoken language or tool making). These sequences include the ability to organize behaviors into hierarchical blocks and understand the relationships between distant elements.

For example, even relatively simple human behaviors such as making a cup of tea or coffee require performing a series of individual actions in the correct order (e.g., boiling the kettle before pouring the water). We divide these tasks into solvable blocks (e.g., boil the kettle, pick up the milk and tea bag, etc.), composed of individual actions (e.g., “grab”, “throw”, “spin”, “pour”). ). Importantly, we can separate related actions by other fragments of behavior (for example, you may have to stop and clean up some spilled milk before continuing). It was unknown if the capacity of flexibly organizing behaviors in this way is either unique to humans or is also present in other primates.

In this new study, published in PeerJ magazineresearchers investigated the actions of wild chimpanzees (our closest relatives) while using tools, and whether the tools appeared to be organized into sequences with similar properties (rather than a series of simple, reflex-like responses). The research was led by the University of Oxford with international collaboration in the United Kingdom, United States, Germany, Switzerland and Japan.

The study used data from a database of decades of video footage showing wild chimpanzees in the Bossou forest, Guineawhere chimpanzees were filmed cracking hard-shelled nuts using a hammer and stone anvils. This is one of the most complex documented natural tool-using behaviors of any animal in nature. The researchers recorded sequences of actions that the chimpanzees performed (e.g., grasping a nut, passing it between hands, placing it on an anvil, etc.), making a total of 8,260 actions for more than 300 nuts.

Using state-of-the-art statistical models, they found that relationships emerged between the chimpanzees’ sequential actions that matched those found in human behaviors. Half of the adult chimpanzees seemed to associate actions that were much later in the sequence than would be expected if the actions were simply linked one by one. This provides further evidence that Chimpanzees plan sequences of actions and then adjust their performance on the fly.

TECHNICAL FLEXIBILITY SIMILAR TO HUMAN

Understanding how these relationships emerge during the organization of action will be the next key goal of this research, but they could involve behaviors such as chimpanzees pausing sequences to readjust tools before continuing, or bringing several nuts close to stone tools that then snap. in a long sequence. This would be further evidence of human-like technical flexibility.

Furthermore, the results suggest that most chimpanzees organize actions in a similar way to humans, through the production of repeatable “fragments”. However, this result did not hold for all chimpanzees, and this variation between individuals may suggest that these strategies for organizing behaviors may not be universal as they are for humans.

Lead researcher Dr Elliot Howard-Spink (formerly Department of Biology, University of Oxford, now Max Planck Institute of Animal Behaviour) said: “The ability to flexibly organize individual actions into tool-using sequences has probably been key to the overall success of humans. Our results suggest that fundamental aspects of human sequential behaviors may have evolved before the last common ancestor of humans and chimpanzees, and then may have been elaborated during the later evolution of hominids.”

Because many great apes perform skilled and technical foraging behaviors, the capacity for these complex sequences is likely shared by all ape species. More research is needed to validate this theory, and is a key goal for the team moving towards biodiversity conservation.