• People naturally form groups with those who are like themselves
  • We have in-built tendency to generalise about people we don't know
  • Instinctively view our group as varied but distant groups as similar
  • Finding a common enemy strengthens the identity of people's own group

Hate crimes against Muslims has tripled in the weeks since the Paris terror attacks that saw 130 people killed by terrorists, according to figures from Scotland Yard.

US Presidential candidate Donald Trump has called for a ban on Muslims entering the country. In contrast no such calls were made after the 1995 Oklahoma bombing, when 168 were killed by two former US soldiers Timothy McVeigh and Terry Nichols - for example to place restrictions on the movements of ex-US military personnel.

The different reactions, says Nick Chater, Professor of Behavioural Science, is down to an in-built tendency to generalise about groups of people we don’t know much about.

On BBC Radio 4’s The Human Zoo Professor Chater, who teaches Behavioural Sciences for the Manager on the Executive MBA, said this tendency to generalise is “hard to avoid."

He added: "We have a lot more information about the things we encounter a lot, things we don’t encounter a lot we are likely to over-generalise because we have no better basis.

“The reaction to the Oklahoma bombers and the killers in Paris is an example of this. In the Oklahoma case we tend to think of the bombers as very different to typical Americans or typical ex-US soldiers, and it would seem extremely odd that all US citizens or  former solidiers had to identify with, would have to apologise for, and actively repudiate those particular individuals. We just don’t think of the Oklahoma bombers as typical of these groups.

“But with the Paris attackers, for many in the West, the killers are somehow identified with a larger group, perhaps even with all Muslims in general. This is very difficult to defend on a rational level, but perhaps a rather natural human reaction because it is a group that, for many, is less familiar.

“We tend to view our group as very varied people, but we view distant groups as more similar.”

The study of group processes and intergroup relations is a rich area for social psychologists. It helps to explain our instinct to categorise people and naturally form groups with those who are like ourselves.

“The mind is very focused on specific cases,” said Professor Chater, who also teaches Principles of Cognition on the suite of MSc Business courses. “When we think of a new person, experience or object, we try to think of similar cases that we have encountered before.

“When we are dealing with ‘the other’ - somebody outside our normal group - we are dealing with something unfamiliar, so we have to make a big leap from the very small number  of similar cases we have seen of ‘the other’ in the past and overgeneralise rather wildly.”

One reason people can be attracted to finding a common enemy is that it strengthens the identity of their own group.

It is easier to define the group when there is an opposition that the group is unified against and can be defined against.

“When we know who we are against it makes us feel more unified,” said Professor Chater. “As we unify in opposition we become more similar to each other, because we are not like them, we are like each other.”

But perhaps as we become more connected through TV and the internet, that group we are in is expanding to include more people.

Professor Chater added: “You can see the whole trajectory of Western morality and political thought as the gradual extension of the group we identify with from very local - our family and immediate neighbours - all the way up to all of humanity.”

Listen to Professor Nick Chater on the The Human Zoo and visit the programme's online laboratory.

To learn more about behavioural science sign up to professor Chater's free online course - The Mind is Flat: the Shocking Shallowness of Human Psychology.