I have a theory that some people when they are out in nature would be more likely to hunt and gather in groups and some would do it alone. These differences would account for a lot of different personalities and ways of thinking in autistics and NTs.
The autistic way to hunt a mammoth would be to chase it until it got tired or to make a strategy to run it off a cliff. in order to do this you would need a lot of endurance and a very long attention span. chasing a large animal requires sometimes days of hunting before it gets tired enough to catch. also you would be required to fixate on the goal and never get bored or wander off. hunting by chasing requires a very good spatial awareness and understanding of how landscape, terrain, topography, and foliage will affect the chase. Also, you would need an encyclopedic knowledge of mammoth feeding patterns, migration patterns, behavior, and reactions to being hunted.
The NT way to hunt a mammoth would be to gather a group of 25 to 30 people. then, they would select a leader and debate a strategy for hunting. hunting in a group requires a lot of quick signals and body language. usually they would chase the animal a little then surround it and attack it. when you are in a group you need to catch enough to support everybody, so it would be important to have a short attention span and if one hunt wasn't successful move to the next target. when it comes time to divide up the meat, the most important and dominant people in the group would get the most meat. so, to survive one would always be in a power struggle with all the members of one's group. hunting by surrounding would only require a general knowledge of surrounding because the hunters could communicate these things to each other easily.
The autistic way to gather would be to consider where berries would likely be, then go find the most efficient way to gather them. an autistic person would always have to gather enough to be completely self supporting. in order to do this they would have to know what kind of soil, landscape, sunlight, water, and altitude the berries would grow at. they would need to have an encyclopediac knowledge of these factors and also be able to predict things like, if there is this kind of soil and the sunlight hits this face of the hill, then will the sunlight and soil on the other side be good for berries?
The NT way to gather would be to spread out over the landscape until someone found a patch. they would then call the other members of the group. since there would be a lot of people trying to get one patch of berries the dominant people in the group would get more. and they would have to find more patches than an autistic person. looking for berries in this way would only require a basic knowledge of surroundings.
On a side note, predatory animals like mountain lions sometimes attack people who walk alone even in this day and age, so autistic people would always have to watch their back. maybe, they would even have to hunt down all the predatory animals in the area so that the animal wouldn't kill them in their sleep.
so, i think that those different life styles our hunter-gatherer ancestors had could have affected personality types today. but, some things that make this theory more complicated is that some people would have hunted as a couple or a small group. also, people always intermarry so a lot of people have different mixes of personality traits, or symptoms.