The Imitation reference article from the English Wikipedia on 24-Apr-2004
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Imitation

Imitation is an advanced animal behavior whereby an individual observes another's behavior and replicates it itself. It has been argued by Susan Blackmore in "The Meme Machine", that imitation is what makes humans unique among animals. Imitation might have been selected as fit by evolution because those who were good at it had a wider arsenal of learned cultural behavior at their disposal, such as tool making or even language.