Autism checklist

Genes for autism are extremely old. Autism was originally adaptive for living alone (when food was scarce). More recently (like 200K-5K years ago), autism was useful in the contexts of small tribes. Neanderthals were supposedly more autistic, but were eradicated by the more social homo sapiens.

It was still useful for tribes to have one or two autistic people who were extremely good hunters, foragers and inventors, even if they lowered the cohesion of the tribe by their asocial nature.

Orangutans are fairly autistic. They are capable of reaching full ecological independence before age 10. They avoid direct eye gazing and direct facing.

Orangutans eat, sleep, hunt, and forage on their own (Delgado and Van Schaik, 2000). They are often described as cautious and introverted, and it has been estimated that Bornean orangutans spend at least 95% of their time alone (Van Schaik, 1999). Orangutans have low interaction and association rates, and only infrequently meet up with conspecifics, often only to mate (Van Schaik and Van Hoof, 1996). They have been reported to congregate in small groups temporarily, but only to eat from a particularly fruit-laden tree. Several specialists emphasize that orangutans have limited social aptitude and tend to prefer solitude (Van Schaik, 1999). Van Schaik (1999) has concluded that, unlike all other species of apes, well-defined communities do not appear to exist in any orangutan population studied so far.

Male orangutans actually spend a greater proportion of their time alone compared to females (most of the time spent between two males is thought to be attributable to random, unintended encounters) (van Schaik, 1999).

Aside from orangutans, all apes, including gibbons, gorillas, chimpanzees, and bonobos are social species, much like humans (Chance and Jolly, 1970). To some degree, it seems that orangutans regressed in their social abilities relative to other apes because, as their group size decreased, pressure from the social environment must have decreased along with it.

Primatologists generally agree that orangutans live solitary lifestyles primarily because the islands of Borneo and Sumatra, where they are found, have poor food density. Relative to the lush African regions that chimpanzees and gorillas inhabit, these islands cannot support large groups of social apes (Delgado and Van Schaik, 2000). If orangutans lived in larger social groups, they would have to travel extremely far (up to 20 miles) each day simply to get enough food to sustain themselves (Sugardijto, te Boekhorst, and van Hoof, 1987). Because orangutans are large animals, and because the trees and bushes in their non-seasonal habitat go through various phases of producing buds, shoots, and fruit, the orangutans must forage through many plants daily to ferret out the right dietary foodstuffs (Delgado and van Schaik, 2000). Because they must traverse so much land everyday in order to obtain a sufficient number of calories, individual orangutans must define large territories for themselves.

(https://journals.sagepub.com/doi/full/10.1177/147470491100900209)

You can see that most of the traits are on the ‘extreme male’ end, which is why autism has been called the extreme male brain. Autistic women fall somewhere between women and men for most traits, but can fall between men and autistic men for some traits. I go through the autism checklist in a YouTube video. The mic is a bit low.