WEDNESDAY, Oct. 14, 2009 (HealthDay News) -- While chimpanzees will help each other upon request, they're not likely to offer help voluntarily, say researchers trying to understand the evolution of altruism.
A Japanese research team studied six pairs of chimpanzees (three mother-offspring pairs and three non-related adult pairs) in experiments designed to find out whether a chimpanzee would give a tool to a partner even if doing so wouldn't bring an immediate benefit.
The chimpanzees were willing to give tools to help their partner, but this usually happened only after the partner had asked for help by holding out an arm or by clapping.
"Communicative interactions play an important role in altruism in chimpanzees," researcher Shinya Yamamoto said in a news release. "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."
The study appears online Oct. 14 in the journal PLoS One.
This type of "help upon request" altruism may be a more economical and effective strategy than voluntary altruism, said the researchers at the Primate Research Institute and the Wildlife Research Center of Kyoto University. Waiting for a request for aid is always helpful, and the effort is never wasted, the study authors noted.
Yamamoto and colleagues said "help upon request" altruism may have initially contributed to the spread and development of altruism during human evolution.
The American Psychological Association has more about altruism.