Monday, May 12, 2008

Rats feel peer pressure too

It's not just humans who succumb to peer pressure - rats do too. Brown rats have a tendency to disregard personal experiences and copy the behaviour of their peers. What's more, the urge to conform appears to be so strong that they will choose to eat food they know to be unpalatable when interacting with other rats that have done the same.

Bennett Galef and Elaine Whiskin at McMaster University in Hamilton, Ontaria, Canada, put rats off cinnamon-flavoured food pellets by injecting the animals with a nausea-inducing chemical after their meals. Given a choice, these trained animals preferred to eat cocoa-flavoured food pellets.

However, when those rats then spent time with "demonstrator" rats that had just eaten and smelt of cinnamon, they regained their liking for it (Animal Behaviour, DOI: 10.1016/j.anbehav.2007.11.012).

Until now, humans and chimps were the only other animals known to conform in this way. Andrew Whiten from the University of St Andrews, UK, says that the discovery emphasises the importance of social learning in the animal kingdom.

The big question now, he says, is why they conform. "It's not immediately obvious why a rat or chimp or human would cast aside what it knows from its own experience and adopt an inferior course of action just because everybody else is doing it."

Original here

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