Children are more likely to seek assistance in a task than chimpanzees, suggesting that a motivation to work together could be part of what makes us "human". Writing in the journal Current Biology, Michael Tomasello from the Max Planck institute for Evolutionary Anthropology, in Leipzig, Germany, and colleagues Yvonne Rekers and Daniel Haun, wanted to test the idea that humans are more motivated to collaborate than our closest relatives, the Chimpanzees.
Both children and Chimps are known to collaborate. They recognize when they need help and actively recruit a partner to assist them. Chimps are also known to choose good collaborators over bad collaborators, so clearly possess the cognitive abilities to understand the need for, and the problems with, sharing a task. However, Chimps generally keep to themselves. They live in groups but most of their foraging is done individually, groups of males only rarely work together to hunt. This gave rise to a hypothesis that motivation, not ability, was behind human collaboration.
To test this, the researchers devised an experiment where the subject, a chimp or a child, could pull a board full of food into their chamber in one of two ways: Either alone; by pulling two ropes simultaneously, or collaboratively; pulling a rope in their chamber while a partner pulled the other. The partners were familiar animals - from the same social group for the Chimps, and the same kindergarten for the children. Both methods resulted in the same amount of food for both test subject and partner, ensuring there was no advantage to one over the other.
Human children chose to collaborate around 78% of the time, significantly more often than did the chimpanzees, only around 58%. This shows that the children chose to collaborate far more than would be expected by chance alone, while the chimps chose randomly.
So why would children prefer to collaborate? One hypothesis is that we have an innate drive for "fairness"; as the partner child was given the same amount of food regardless of whether they cooperated or not, they could be seen to be getting a "free ride" on the other child's efforts. To test this, the researchers devised a second test, where the partner child only received a food reward in secret. Despite this, the children still chose the collaborative board significantly more often than by chance alone.
This shows that children are more motivated to collaborate than Chimps. The authors speculate:
"Collaborative foraging may well have been a key behavioural domain in which humans evolved a suite of new proximate mechanisms, both cognitive and motivational, for collaborating with others in ways that eventually led to the many complexities of modern human societies."
They now propose similar experiments to compare different primate species and explore the evolutionary history of collaboration.
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