A narrative of human evolution.

Scientists acknowledge, both male and female, that there is a serious problem of gender disparity in most of their fields. But there is an obstacle in getting the science community to truly understand the gravity of their gender problem, and I think even now in our “enlightened” age, many scientists still do not take the problem seriously. Men in science should be taking it personally, but they are not, and they therefore do not pursue solutions with the appropriate level of sincerity.

What most scientists do not understand – here I mean all genders – is that the science itself is suffering for the lack of women. In truth from a lack of diversity in general, but I want to use a specific example here which will highlight the gender problem.

It does seem to be a common perception, among those outside the community, as well as among many inside, that science is progressing in a largely unbiased way. The fact that we are necessarily approaching our questions from an anthropocentric worldview, though, seems perfectly clear. More important for the narrative here is that most scientists – in particular Darwin himself – are men. I am going to suggest that the prevailing narrative of human evolution is an male centered one, and this bias misses what might actually be the more important female half of the story:

The hair on most men’s arms is coarser and darker than that of boys, and it is not as fine as the hair most women retain into adulthood – this is called vellus hair. Vellus hair, then, is juvenile trait retained into adulthood, and it is more common for women to retain this trait than men. You will also note that this pattern does not occur among bonobos and common chimps. The evolutionary trend of retaining juvenile traits is known in biology as neoteny, and it has occurred for other species as well, and it seems to be associated with a pattern of domestication: dogs, cows, pigs, and cats have all undergone neotenous changes over the course of the last several thousand years. Vellus hair is a physical trait, like the diversity of fur colors which have appeared for dogs and cats, but it is not primarily the physical trait that is being selected for. Actually, it is a set of behavioral changes that are being selected – the physical traits are correlated with changes in behavior due to hormones.

It has been argued by some anthropologists that humans are self-domesticated apes(1). The implication of the changes described above being more pronounced in women is that the selective process has acted to a greater degree on them than men. This means the male-centeric idea of early hominids who stood up to use tools out on the savannah, and communicate amongst each other to better hunt prey is failing to account for half of the species obviously, but less obviously that the other half of the story may be the more important part!

Archeological finds within the last few years have shown it likely that humans were upright walkers prior to leaving the forests (2). This suggests the particular changes in brain development for humans are not solely associated with the opportunities of having the hands free, and ingenious new tool use. This was, and for many still is part of the standard Darwinian narrative. But if not tool use, what are the particular behavioral changes of domestication, assuming humans underwent these to reach their present state?

A scene from one of the best NOVA episodes:

Humans are more trusting of one another. Humans also have greater empathy and more sophisticated theories of mind than apes. There is also less aggression, at least towards the in-group if not conspecifics generally. I don’t think I will be accused of gender bias if I suggest that females are less aggressive than males. There is enough data to support this, and it is well associated with measurable hormone differences.

I remember once hearing of a study, which I cannot find right now, that reported upwards of 60% of the words spoken by people are not for communicating useful information at all, but are mostly gossip. If you believe that women talk more than men do (3) and that 60% should apply to them as well, this suggests that gossip and other kinds of social communication may actually be the primary purpose of language. Taken together with the ape study I have this hypothesis:

Nature has selected for less aggressiveness, and greater levels of sociality within the in-group. Especially for children, it became important to learn from mothers and other members of the tribe or community. This required that children be receptive and trusting, and that receptiveness came along with a certain gullibility. I am suggesting this is the origin of the “disposition A” I discussed in a prior post. Also, to the extent that these evolutionary changes are more pronounced in women it also suggests that they have been subject to a greater selective pressure in this direction. Humans had to evolve a system-wide substrate for the preservation of cultural mimetic information, and a perhaps unavoidable consequence of that was also a propensity for superstition and ritual.

There is unfortunately the sexist implication that women are better at learning from others at the expense of a capacity to explore new knowledge on their own, which I think legitimates the kind of sentiments expressed by Larry Summers(4). I won’t try to defend this – I don’t think there exists and there may never exist experimental data to back up an assertion that goes that far. This returns us to where the post started: without women participating equitably in the scientific process, their stories and their perspectives will go largely unexplored, or explored by men who would rather proliferate theories of females laying on their backs, waiting for males to come home with food (4).


  1. http://www.sciencemag.org/content/346/6208/405.full
  2. http://humanorigins.si.edu/evidence/human-fossils/species/ardipithecus-ramidus
  3. This is by no means a settled question in the literature despite my personal experience http://www.hsph.harvard.edu/news/features/do-women-talk-more-than-men/ .
  4. http://bulletin.swarthmore.edu/bulletin-issue-archive/index.html%3Fp=145.html. The suggestion that males have a greater variance in scientific ability than females is one my hypothesis would be sympathetic too. Autism is more common among males, and this helps push them towards the far upper and lower ends of the bell curve. These are impossible things to quantify, though.
  5. Owen Lovejoy: http://www.discovery.com/tv-shows/other-shows/videos/i-ardipithecus-i-males-become-providers/, Rebecca Solnit: http://harpers.org/archive/2015/06/shooting-down-man-the-hunter/1/