True enough people tend to associate with people they find similar, especially when they are in a stressful situation.

The question is though, what similarities do they pick out? And the odd thing is how, rather than age and appearance and general style (scruffy, sharp etc) people so often pick out "race" as the relevant factor.

I always remember how years ago on a trip to Morocco we were wandering through the souk, and it was a but scary. All around us were Arabs and Berbers, friendly enough, but looking so different from what we were used to - and suddenly we saw this black guy selling corn-on-the-cob, and he looked so familiar. I mean, he was Moroccan too, and we'd no more (and no less) in common with him than anyone else in the street, but he looked just like the blokes we were used to seeing in the street markets back home in London. And the whole place felt much less scary.