Conformity. It's everywhere you look in human society. We're all copying each other like crazy all the time, often without realising it. It's well established by researchers - like Solomon Asch in his famous experiment in 1955 - that people will disown the evidence of their own eyes in the struggle to conform with other people. (You can try a simple version of it here - damn it I conformed!)

But what evidence is there from other species? A recent study has shown that chimpanzees conform to each other just like humans - even when they don't need to.

In this study, two different social groupings of chimps were intially taught two different ways of getting food out of container. Both worked equally well and both groups were eventually exposed to both methods. Despite this, and after trying out the competing technique for a short period, each social grouping stuck to its own method in the long-term.

The experimenters argue that this provides a parallel of the way human social groups establish a behavioural 'norm'. For example forming an orderly queue at the post office is a culturally transmitted norm of which we British are strangely proud. I'd like to see chimps form a queue!
Nature
The Guardian