In archaic ancestors it is associated with robust species with broad faces. In modern man it is associated with long, narrow faces and relatively large brains.
For archaic ancestors the purpose has been associated as an adaptive mechanism for running with a protuding face, in opposition to the flatter faces of modern man.
In modern man it is associated with space for a relatively large brain housed in a narrow cranial base.
Are people with Aspergers more likely to have narrow faces and occipital buns?
One could look through the pictures of individuals that post here to try to determine the narrow face part, from an anecdotal perspective.
Interestingly, that type of face (dolichocephalic) has been has been associated with trustworthiness in males, and lower levels of testosterone, whereas a broad face is associated with higher levels of testosterone and aggresion. Also interesting that lower IQ test results are associated with very low levels of testosterone as well as very high levels of testosterone.
http://en.wikipedia.org/wiki/Occipital_bun
http://en.wikipedia.org/wiki/Dolicocephalic
http://www.livescience.com/6169-guy-trustworthy.htm
To suggest that there is any structural similarities between the occipital buns in modern humans and the occipital buns in Neanderthals is counterintuitive, because it is associated with robust features in archaic man, and associated with domesticated features in modern man.
The San Bushman are measured as having no Neanderthal DNA, however they have narrow faces, relatively large brains, are slight of body, and are known to be in the minority of humans that still possess an occipital bun.
http://www.pbs.org/wgbh/nova/transcripts/2902neanderthals.html
Long faces are also associated with the Nordic master race myth that led to all kinds of problems last century, and still linger in Supremacy groups.
Interesting description from the early 20th century, when the idea was well known and accepted.
Quote:
Among all the disputes and uncertainties of the ethnographers about the races of Europe, one fact stands out clearly — namely, that we can distinguish a race of northerly distribution and origin, characterized physically by fair colour of hair and skin and eyes, by tall stature and dolichocephaly (i.e. long shape of head), and mentally by great independence of character, individual initiative, and tenacity of will. Many names have been used to denote this type, ... . It is also called the Nordic type.[46]
This mythical race was identified within the geography of historical Northern Europeans, identified as having Occipital Buns.
It's interesting how many association one can come up with, with this kind of thing.