The people at the end of the chain were far more knowledgeable than those at the start

From Stereotypes 'evolve like language', say researchers by Jonathan Ball.

I have long considered the stereotype of stereotypes to be sloppy thinking and a desire to ignore reality in pursuit of idealism. The stereotype of stereotypes is that they are ignorant, sloppy, inaccurate and generally reprehensible. My view is that stereotypes are simply one among many usually useful heuristic devices for dealing with a complex and rapidly changing world. We have limited time and bandwidth for absorbing new information. We need ways of communicating complex situations without boring people to death or exhausting their patience. Very often, the recourse is to stereotyping - rendering an aggregation of individual variances into a synthesized average which is often true in general but may be wrong in particulars.

That is not to say that there aren't negative stereotypes (which may still be usefully accurate) or wrong stereotypes. It is simply to observe that stereotyping fulfills a useful function as long as we maintain some awareness of its potential shortcomings. Emphasis added:

The team then asked a volunteer to learn the characteristics assigned to each one. The information retained by the volunteer was then fed down a communication chain.

What started out as jumbled and complex individual characteristics and traits ended up encompassed in sets of stereotypes.

Character traits became inextricably linked with form and colour - for example, blue aliens might be perceived as arrogant, pushy and untrusting.

As Dr Martin explained: "Information becomes simpler, more structured and more learnable over time" - so much so that the people at the end of the chain were far more knowledgeable than those at the start.

"It's essentially what stereotypes are - massively over-simplified but easily learnable associations between social groups and bits of information," Dr Martin told BBC News.