What is autism?

I kinda think of the main clusters of symptoms as: (1) sensory sensitivity, (2) social symptoms, (3) different “learning algorithm hyperparameters”.

More specifically, (1) says: innate sensory reactions (e.g. startle reflex, orienting reflex) are so strong that they’re often overwhelming. (2) says: innate social reactions (e.g. the physiological arousal triggered by eye contact) are so strong that they’re often overwhelming. (3) includes atypical patterns of learning & memory including the gestalt pattern of childhood language acquisition [LW · GW] which is common but not universal among autistic kids.

People respond to (1) in various ways, including cutting off the scratchy tags at the back of their shirts, squeeze machines, weighted blankets, etc., plus maybe stimming (although I’m not sure if that’s the right explanation for stimming).

People respond to (2) by (I think) relating to other people in a way that generally avoids triggering certain innate social reactions. This includes (famously) avoiding eye contact, but I think also includes various hard-to-describe unconscious attention-control strategies. So at the end of the day, neurotypical people will have an unconscious innate snap reaction to (e.g.) learning that someone is angry at them, whereas autistic people won’t have that snap reaction, because they have an unconscious coping strategy to avoid triggering it, that they’ve used since early childhood, because the reaction is so unpleasant. Of course, they’ll still understand intellectually perfectly well that the person is angry. As one consequence of that, autistic people (naturally) have trouble modeling how neurotypical people will react to different social situations, and conversely, neurotypical people will misunderstand and misinterpret the social behaviors of autistic people.

Anyway, it seems intuitively sensible that a single underlying cause, namely something like “trigger-happy neurons” (see discussion of the valproic acid model here [LW · GW]), often leads to all three of the (1-3) symptom clusters, along with the other common symptoms like proneness-to-seizures and 10-minute screaming tantrums. At the same time, I think people can get subsets of those clusters of symptoms for various different underlying reasons. For example, one of my kids is a late talker with very strong (3), but little-if-any (1-2). He has an autism diagnosis. (I’m pretty sure he wouldn’t have gotten one 20 years ago.) My other kid has strong nerdy autistic-like “special interests”—and I expect him to wind up as an adult who (like me) has many autistic friends—but I think he’s winding up with those behaviors from a rather different root cause.

Much more at my old post Intense World Theory of Autism [LW · GW].

I'm also interested in book recommendations or recommendations for other resources where I can learn more.

I thought NeuroTribes was really great, that’s my one recommendation if I had to pick one. If I had to pick three, I would also throw in the two John Elder Robison books I read. In Look Me in the Eye, he talks about growing up with (what used to be called) Asperger’s; even more interestingly, in Switched On he describes his experience with Transcranial Magnetic Stimulation, which led (in my interpretation) to his reintroduction to those innate social reactions that (as mentioned above) he had learned at a very young age to generally avoid triggering via unconscious attention-control coping strategies, since the reactions were overwhelming and unpleasant.

@Steven Byrnes [LW · GW]' intense-world theory of autism [LW · GW] seems like the sort of thing you're looking for.

I'm not sure there is an underlying framework. As in much of psychiatry there isn't a robust theoretical framework for the diagnosis. It's more like of you have A1 you are more likely to have B2 and c3 and the more subcategories you qualify for the more likely is it that strategy d or e will work to make you functional in society. It's all trial and error IMO. As for literature I'd recommend "the curious incident with the dog in the nighttime"