Saturday, March 10, 2007

The connection between female infanticide and autism

Surely I'm not the first person to speculate about this connection, but so far failed to discover anything via Google.

The nature-nurture debate rages on, especially now that Simon Baron-Cohen is claiming that Autism is associated with masculinity because autistics are systematizers and males are systematizers, while females are empathizers.

This is mostly based on speculation and big stretches, that are effectively countered by the work of Elizabeth Spelke.

But it is indisputable that more boys than girls are autistic, with estimates ranging from 4:1 to 10:1.

It is also indisputable that infanticide was practiced far and wide througout human history, but especially female infanticide:

There is ample historical evidence to document the incredible propensity of parents to murder their children under an assortment of stressful situations. In nineteenth century England, for example, infanticide was so rampant throughout the country that a debate over how to correct the problem was carried out in both the lay and medical press. An editorial in the respected medical journal Lancet noted that "to the shame of civilization it must be avowed that not a State has yet advanced to the degree of progress under which child-murder may be said to be a very uncommon crime.

Infanticide has pervaded almost every society of mankind from the Golden Age of Greece to the splendor of the Persian Empire. While there are many diverse reasons for this wanton destruction, two of the most statistically important are poverty and population control. Since prehistoric times, the supply of food has been a constant check on human population growth. One way to control the lethal effects of starvation was to restrict the number of children allowed to survive to adulthood. Darwin believed that infanticide, "especially of female infants," was the most important restraint on the proliferation of early man.


Infanticide is not necessarily actively practiced - that is, the parents don't outright murder the baby, but rather cause it to die through selective neglect. This from "Health care allocation and selective neglect in rural Peru."

In spite of the fact that infanticide was widely practiced, it was still a difficult thing to do. Anthropologist Marvin Harris suggested that infanticide was so repugnant that until the invention of more humane forms of birth control, societies responded to times of abundant resources by allowing more children to live - eventually resulting in scarcer resources due to overpopulation.

While it must be difficult to kill any baby, it certainly must have been easier for parents to kill babies that refused to interact with them. Two of the three classic symptoms of autism are stunted social interactions.

According to the National Autism Association:

(Indicators of autism include):
  • failure to develop peer relationships appropriate to developmental level
  • lack of social or emotional reciprocity

  • stereotyped and repetitive use of language or idiosyncratic language

  • apparently inflexible adherence to specific, nonfunctional routines or rituals
  • persistent preoccupation with parts of objects

    Is it really a stretch to suggest that the reason that the ratio of male:female autism is so extreme is because female infants that displayed symptoms of autism were much more likely to be victims of infanticide?

    It isn't just rates of autism though - baby girls are hardier in general than baby boys, and it seems likely to me that a plausible explanation is that baby girls have been selected for hardiness - the weaker ones died from selective parental neglect that was not practiced as much on baby boys.

    And there ends the debate on nature vs. nuture - because if my theory is correct, it is cultural selection that resulted in a higher incidence of autism in boys, rather than some testosterone-autism connection that Baron-Cohen suggests.

    Obviously this hyposthesis needs to be tested. But it's no more implausible-sounding to me than plate tectonics.