Over the last week I interviewed a large number of med students each for 10mins. I asked them all the same questions. I noted that the women flushed on their face and neck far more than men (x5-6 as often). What might be the evolutionary advantage of that? My initial thoughts:-

1. more attractive for finding a mate (though can't think why that might be)

2. increased vasodilation might stimulate the release of various pheremones (again seems unlikely).

Anyone got any better ideas?

Actually I would go for point 1. It could well be a sexual signal (or at least the tendency to do so more often / easily in women may have originated as one). The face and neck are highly visible parts of the body, and during courtship would be a focus of attention so something that suggests a clear positive messgae of excitement such as blushing would be a useful signal. Here it has merely been co-opted or perhaps more likely simply can't be turned off, during any for of excitment or nervousness.

Another possible reason is that men typcially have hair necks and faces (well, beofre the advent of shaving of course) and so if you wanted to loose heat, the face a neck are a poor choice to try and flush since they would be insulated. It could be a minor zone of heat loss for women and thus they blush when hot or nervous and want to try and control their tempreature.

But, David, what on earth were you saying to them?!

I was asking them specific questions relating to the signs and symotoms of various common medical diagnoses. I presume (and hope) it was the stress of the interview rather than anything inappropriate I said!

An interesting footnote to this question. A study into blushing noted what David spotted, that women blush more than men. The argument is that it is a signal of honesty (and thus carries a cost) and shows that you care about being truthful. So it is evidence for David's first hypothesis.

I'm afraid this was something I caught on Radio 4 and can't, as yet give a link to the study.

"Hope is a duty from which palaeontologists are exempt."
David Quammen

I think that everyone is missing another point here - there was potentially an observer effect. David may have been causing women to flush because they were aroused by his presence - and who can blame them?

If you look at my picture on the home page you will see that is an unlikely hypothesis, though now I think of it Paolo did not say that I aroused them in a positive manner!

I'm interested in finding out why we blush as it seems to be a strange thing for our bodies to do!

Let me know if any of you have any opinions/thoughts on this.

I am going to try and have a dig through the literature.

Scientific American has something to say about this in the context of embarrassment - see http://www.scientificamerican.com/artic … arrassment
The comment also refers to the article “The remedial value of blushing in the context of transgressions and mishaps” by Corin Dijk, Peter de Jong & Madelon Peters; Emotion 9: 287-291, 2009 (downloadable via google).