Although this is the first piece of research to demonstrate the influence of perceived ethnicity (just one group marker out of many possible ones) on the firing pattern of the neurons, it could have been expected that they would be affected by other parts of the brain which deal with the in- or out-group status of external actors in social situations.

Mirror neurons - so called because they fire when human beings observe actions by others which are present in their own repertoire - are heavily involved in the exercise of intentionality, ie the ability to recognize and respond to the existence of mind in others.

Although the researchers use the word culture in characterizing the brain's classificatory structures applied to other people and their behaviour, this is a loaded word, and it is cleaner and more accurate to suppose that the brain works in terms of groups rather than anything as sophisticated as 'culture'.

People justify their adverse reactions to others (racist, feminist, fattist, sexist or whatever) by asserting that there is a cultural difference, while in fact what is going on is at least initially just a groupish difference. We label the bundle of characteristics that defines our group, its 'culture', and contrast it against the 'cultures' of other groups, but this is a purely verbal distinction that probably doesn't reflect the way in which the brain works in assessing group membership at a basic level based on individual traits and behaviours. If people would just understand that evolution has made us groupish for sound social reasons, then they might be able to be more dispassionate about people belonging to other groups.

If the dear little mirror neurons can be influenced by the brain's observation of another person's out-group status, maybe we can learn to influence them back again with another part of the brain!