Chimps can learn more efficient ways to use a tool by watching what others do, according to research published January 30 in the open access journal PLOS ONE by Shinya Yamamoto and colleagues from Kyoto University and Kent University, UK. Their study presents the first experimental evidence that chimps, like humans, can watch and learn a group member's invention of a better technique.

Chimps in the study were provided juice-boxes with a small hole and straws to drink with.

One group of chimps used the straws like dipsticks, dipping and removing them to suck on the end, while the other group learned to suck through the straw directly.

This video shows close observation and a subsequent switch in technique. Pal (out of sight in the first view) closely observes the demonstrator, then fetches a tube from the floor (out of sight), and then proceeds to suck the remainder of the juice in the bottle container. Pal had just performed the "dipping" technique prior to observing the alternate technique being demonstrated during the same trial. Credit: Citation: Yamamoto S, Humle T, Tanaka M (2013) Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More Efficient Tool-Use Technique. PLOS ONE 8(1): e55768. doi:10.1371/journal.pone.0055768.

Learning both techniques required the same cognitive and motor skills, but chimps that drank through the straw got considerably more juice in a shorter amount of time.

When the first group of chimps watched either a human or a chimp demonstrate the more efficient 'straw-sucking' technique, all of them switched to using this instead.

This video shows the "dipping" technique performed by chimpanzee Ayumu. Note that he uses his mouth to insert the tube into the bottle. In form, his technique is identical to the "straw-sucking" technique. However, instead of leaving the tube in and retrieving the juice via sucking, he removes the tube and licks the tip. Credit: Citation: Yamamoto S, Humle T, Tanaka M (2013) Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More Efficient Tool-Use Technique. PLOS ONE 8(1): e55768. doi:10.1371/journal.pone.0055768.

The study concludes, "When chimpanzees are dissatisfied with their own technique, they may socially learn an improved technique by closely observing a proficient demonstrator."

According to the authors, their results provide insights into the cognitive basis for the evolution of culture in chimpanzees, and suggest ways that culture could evolve in non-human animals.

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More information: Yamamoto S, Humle T, Tanaka M (2013) Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More Efficient Tool-Use Technique. PLOS ONE 8(1): e55768. Journal information: PLoS ONE Yamamoto S, Humle T, Tanaka M (2013) Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More Efficient Tool-Use Technique. PLOS ONE 8(1): e55768. doi:10.1371/journal.pone.0055768