Sharing: the difference between man and ape?
THE ABILITY TO SHARE knowledge and learn from one another may be the key difference between people and chimpanzees that helped humans to dominate the modern world, scientists suggest.
The new research, published this week in the journal Science, aimed to discover what has allowed humans to establish ‘cumulative culture’, or a gathering of knowledge that ratchets up with improvements in technology over time.
While previous studies have shown that chimps can learn from each other, none have compared their abilities to humans in the same tests, and scientists have long debated what exactly is needed to build up increasingly complex cultural knowledge.
Testing behaviour
The current study compared groups of three- and four-year-old children to separate groups of chimpanzees and capuchin monkeys, all of whom attempted to get treats out of a three-step puzzle box. Chimps and capuchins largely failed to advance in the three levels, with just one chimp reaching stage three after 30 hours and no capuchins attaining that level in 53 hours.
However, five of the eight groups of children tested had at least two members who reached stage three of the puzzle. The difference was that children were better able to learn from watching demonstrators and to communicate and share their knowledge with peers than the monkeys, the team of US, French and British researchers say.
Kids also showed measures of goodwill, or ‘prosocialty’, that their primate cousins did not.
Learning to share treats
“Teaching, communication, observational learning, and prosociality all played important roles in human cultural learning but were absent (or played an impoverished role) in the learning of chimpanzees and capuchins,” says the study.
Children were often observed to tell each other how to advance, saying things like, “push that button there,” or they gestured to show a comrade what to do. They also copied each others’ actions more often than monkeys did, and 47 per cent spontaneously shared a treat with a pal. Chimps and capuchins never shared their treats this way.
That kind of sharing shows that humans understand the need to advance for the greater good, suggests the study. “If individuals voluntarily give rewards to others, this signifies an understanding that others share the motivation of achieving the goal that they had achieved,” it says.
“In contrast, the chimpanzees and capuchins appeared to interact with the apparatus solely as a means to procure resources for themselves, in an entirely self-serving manner, largely independent of the performance of others, and exhibiting restricted learning that appeared primarily asocial in character.”
Insights into cumulative culture
The study was led by Dr L.G. Dean of the University of Saint Andrews in Britain, and included colleagues from the University of Durham, the University of Texas, and University of Strasbourg in France.
In an accompanying commentary also in Science, psychologist Professor Robert Kurzban of the University of Pennsylvania and anthropologist Professor Clark Barrett at the University of California, Los Angeles, suggested the riddle of human advancement may be more complicated.
“This work provides many valuable new insights into the question of cumulative culture,” they write. But given the complexity of the human psyche, other variables “might be responsible for both between-species differences and within-species effects,” such as the ability to sense whether a comrade needs help learning, they add.
Also, since the human culture has evolved to such a high degree, any number of steps in that process may have set us apart from apes, and it may have happened many centuries ago and thus cannot be measured today, the experts argue.
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