There's a research paper just out which has gained itself some press: "High heels as supernormal stimuli: How wearing high heels affects judgements of female attractiveness". It's described in the popular press as "proving" that high heels make women attractive, and that's fair enough but it's obviously not very surprising news given that high heels are widely known in current Western society to have that association. The research paper is slightly more specific than that: it finds that whatever "information" is transmitted to the viewer by high heels is even transmitted when we can see nothing but a handful of moving dots, hiding everything about the viewee except their gait.
That's interesting. But unfortunately, the authors go on to make one further step, which strikes me as a step too far - namely they infer that this reflects some evolutionary explanation for the popularity of high heels. The word "supernormal" in the title refers to the idea that high heels might cause women to walk in a way which exaggerates female aspects of gait, i.e. makes them walk even more unlike males than otherwise. There is indeed evidence for this in their paper. But the authors explicitly test for whether the "female" aspects of gait correlate with attractiveness judgments, and they find insignificant or barely significant correlations.
(Technical note: two of the correlations attain p<0.05, but they didn't control for multiple comparisons, so the true significance is probably lower. And the correlations I'm talking about now are in their Table 2, which is looking at differences within the high-heel category and within the flat-shoe category. The main effect demonstrated by the authors is indeed significant: viewers rated the high-heel videos as more attractive.)
So what does this suggest? To me it seems they've demonstrated that
(a) high heels affect gait (as you can tell on most Friday nights in town), and
(b) people recognise the change in gait as being associated with attractiveness and femininity.
But this second finding can just as easily be explained by cultural learning as by something evolutionary, despite the fact that the paper was published in "Evolution and Human Behavior".
In fact, (b) could conceivably be caused by a conjunction of:
(b1) people recognise the change as being caused by high heels (whether consciously or not); and
(b2) people recognise that high heels are associated with attrractiveness and femininity.
(This b1-and-b2 scenario is also a potential explanation for their second set of findings, in which the gaits of high-heeled walkers are less often mistaken for men.)
All of which means that I don't think these experiments manage to discern any difference between effects caused by evolved factors and effects caused by cultural learning. Given that, the obvious way to test that difference would be to show the dot videos to viewers who grew up in a non-Western society which doesn't have a tradition of high heels. (Not a convenient test to do - but I'd definitely be interested in the results!)
Here's one quote from their results, about a minor aspect, whether male or female onlookers have different opinions:
"note that there was no shoetype-gender interaction, showing that both males and females judged high heels to be more attractive than flat shoes. [...] furthermore, there were high correlations between male and female attractiveness ratings of the walkers in both the flat and heels condition demonstrating that males and females agreed which were the attractive and unattractive walkers."
So, in this study, the male and female onlookers showed the same pattern of response to the presence of high heels. Does this perhaps hint that the difference might be learned, rather than from some presumed phwoar-factor inbuilt in men?
This study is an example of what I see as a frustrating tendency for people in biological disciplines to do interesting quantitative studies, but then to plunge into the discussion section and make unwarranted generalisations about the evolutionary reasons for something's existence. As well as invoking evolution, in this case they also discuss women's motivation for how they dress:
"Therefore we suggest that one, conscious or unconscious, motivation for women to wear high heels is to increase their attractiveness."
Firstly, this study explicitly does not explore women's motivations, in any sense. It only studies judgments made by outside observers. Secondly, as the authors have already acknowledged,
"High heels have become a part of the uniform of female attire in a number of different contexts and as such are part of a much more complex set of display rules."
I don't dispute that attractiveness might be a more important motivation for some than other motivations (fashion, identity, confidence, social norms, availability, symbolism), but let's not imply that this hunch is an empirical finding, please. The association of high heels with attractiveness is already a common trope, so the idea that women might be motivated to buy into that trope is perfectly plausible, but this study throws no light on it.
Still, as I said, the main finding is interesting: the differences in gait induced by high heels, and the rating of such gaits as attractive, are demonstrated to be easily perceivable even in a display reduced to a handful of green dots.