Time for a break from the NSA story. While doing actual work, I ran across a fascinating study (behind subscription wall) in Evolution and Human Behavior. It's called 'Sex differences in response to children’s toys in nonhuman primates (Cercopithecus aethiops sabaeus)'.
Here's what it's about: as most parents know, little boys tend to be more interested in toys like trucks, and little girls in toys like dolls. (I was an exception: someone gave me a doll once, and I dissected it.) There is no obvious way to decide whether this is innate or a cultural artifact by watching human children. So why not see whether the same gendered toy preferences exist in, oh, vervet monkeys?
Guess what? They do.
"The percent of contact time with toys typically preferred by boys (a car and a ball) was greater in male vervets (n = 33) than in female vervets (n = 30) ( P < .05), whereas the percent of contact time with toys typically preferred by girls (a doll and a pot) was greater in female vervets than in male vervets ( P < .01). In contrast, contact time with toys preferred equally by boys and girls (a picture book and a stuffed dog) was comparable in male and female vervets. The results suggest that sexually differentiated object preferences arose early in human evolution, prior to the emergence of a distinct hominid lineage."
(Graphs and photos below the fold.)
Description, from the article: "Fig. 1. Percent contact (means±S.E.M.) with "masculine," "feminine" and "neutral" toys for male and female vervets. Percent contact with "masculine" toys is greater in male than in female animals (P<.05) and percent contact with "feminine" toys is greater in female than in male animals (P<.01). In contrast, there is no sex difference for percent contact with "neutral" toys."
From the article: "Fig. 2. Examples of a female and a male animal contacting toys. The female animal (left) appears to be conducting an anogenital inspection of the toy doll, similar to inspections of infant vervet monkeys. The male animal (right) appears to be moving the car along the ground in a manner similar to that a child might use."