‘Conformity’ in Norway rats?

In a recent paper, Whiten & van Schaik (2007, Philosophical Transactions of the Royal Society of London, Series B, 362, 603–620) suggested that although a tendency to conform to the behaviour of others is widespread in animals, only chimpanzees and humans will ignore personally acquired knowledge of a superior behavioural alternative and copy the behaviour of others expressing a less effective behaviour. Here we show that ‘observer’ Norway rats, Rattus norvegicus, that have learned either that one food is toxic and another safe or that one food tastes good and another is less palatable will ignore their personal experience and choose to eat an unpalatable or presumably toxic food after interacting with ‘demonstrator’ rats that have eaten that food. Such observer rats will eat as much unpalatable or presumably toxic food after interacting with demonstrator rats that have eaten them as they would if they had no personal experience of superior alternatives. We discuss the similarity of rats' total reliance on socially acquired information when in possession of conflicting personal information to ‘conformity’ in chimpanzees and humans.