Washington, Oct 15 (Inditop.com) Chimps tend to help their own, without expecting direct gain or reciprocation, but only on request, say scientists.
Shinya Yamamoto and colleagues at the Primate Research Institute (PRI) and Wildlife Research Centre (WRC) of Kyoto University, studied six pairs of chimpanzees (three mother-offspring pairs and three non-kin adult pairs,) in two different experiments.
The experiments were designed to test whether the chimps would transfer a tool to a counterpart even if it brought no immediate benefit to themselves.
In each case, two chimpanzees were situated in two transparent booths. In the straw-use situation the chimp needed access to a straw before being able to drink juice.
In the stick-use situation the chimpanzee would need access to a stick to drag a juice reward back into the booth.
In the first experiment, the two chimpanzees would have access to the opposite tool needed to obtain the reward in their booth. The chimpanzee that needed the straw would have access to the stick and vice-versa.
In the second experiment, the mother-offspring pairs were tested in a situation where there was no opportunity for reciprocation because each individual was assigned a fixed role-giver or recipient for 24 trials before the roles were reversed.
Researchers found that the chimpanzees did transfer tools in order to help their partner. This happened only after the partner had actively solicited help (by poking its arm through a hole in the booth, for example, or by clapping), even when there was no hope of reciprocation from the partner (as in experiment 2) or when they were unrelated.
“While humans may help others without being solicited, the chimpanzees rarely voluntarily offered an effective tool to a struggling partner. Indeed, simple observation of another’s failed attempts did not elicit voluntary helping in chimpanzees,” said Yamamoto.
The findings were published in the Wednesday edition of the open-access journal PLoS ONE.
