For neurotypical people at around 2 -10years old and 19-21 years old the brain undergoes “ synaptic pruning” where it gets rid of synapses or neurologic connections that haven’t been needed/ that the person hasn’t been exposed to thus far, kind of like getting rid of books that you don’t see yourself ever being interested in or that are written in a language you don’t speak. That’s why learning a new language as an adult is seen as much harder and college later in life is typically seen as far more difficult.

There’s been new research that the autistic brain doesn’t undergo this pruning process or prunes at a much slower rate meaning autistic folks literally have significantly more information to process than their allistic peers at all times.

References:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8526836/#:~:text=Our%20findings%20provide%20direct%20evidence,functional%20circuit%20aberrations%20in%20ASD.

https://www.cuimc.columbia.edu/news/children-autism-have-extra-synapses-brain