FRIENDSHIP doesn’t run deep for captive chimpanzees. In a lab experiment, chimps failed to lend a helping hand to their fellows even though doing so wouldn’t have inconvenienced them.
Joan Silk of the University of California, Los Angeles, and her colleagues set captive chimps tests in which they could either choose to obtain a food reward for themselves, or for both themselves and another group member.
Only in around half the tests did the experimental subjects let another animal get a reward. And they were just as mean when another chimp was watching them (Nature, vol 437, p 1357).…
