And that is a question that is very happily answered by my explanation of the increase. Because the cause I invoke accumulates postnatally, it only impacts at a later age, whereas the classic genetic causation would impact from long before birth. And so one would indeed expect the new causation to commonly be less severe than the earlier variety.
1. Uta Frith, Autism: A very short introduction, OUP 2008
Defeating Autism by Michael Fitzpatrick: Shallow critiques of the Holmes and Bradstreet studies of mercury
Some people think it is somehow puzzling that an individual can have such extraordinary ability in some obscure form of calculation or calendar-memorising or such-like. Especially if they are not particularly high IQ. I don't find it particularly suprising myself, at least not more so than the already amazing things that the brain of the average person is capable of anyway.
For instance if you have any experience of cheapo binoculars you will know that the human visual system has an ability to coordinate two misaligned images into one. And indeed it does this all the time even when binoculars are not involved and even when stereoscopics and other factors make the images disalike. This effortless merging of binocular images must take some rather substantial hardwired computing power.
A second less obvious example came to my attention after I was attacked by a thug and left for dead. A few weeks later I was amazed to find that my right ear was hearing sounds half a semitone sharper than my left ear. Which causes all music to sound very unmusical indeed. This problem, the technical name of which I have forgotten, resolved itself on the 13th day just before it had driven me completely bonkers. But again, it shows that the auditory brain must be likewise effortlessly mapping together the disparate sounds from the two ears, even while our attention is concentrated on other things such as understanding or appreciating the sounds in question.
These high-power computations are performed without effort in the brains of even the most average of people. Let us combine that fact with the observation that in normal development, some neurons have to "migrate" their axons and dendrites significant distances to establish connections with other parts of the brain or body. Under certain conditions it can be expected that such migrations will get misdirected, and this would in respect of sensory neurons quite credibly produce the mix-up of sensations that is synaesthesia.
Meanwhile there could occasionally be another sort of misdirected migration-connection, in which an area which would normally be innately-assigned to one of those complex innate functions such as binocular vision or hearing gets connected to some other inputs and outputs and thereby recruited for some other task instead. And would thereby produce, rarely, one or other savant syndrome ability.
(except that genius is now totally invisible)
| [One of the cases which Eysenck did not mention here was that of Ludwig Boltzmann, whose outstanding discovery of statistical thermodynamics was ridiculed by university professors for ten years till he took his life.]|
[page 147:] Less often remarked, but possibly even more insidious, is the resistance by scientists to scientific discovery [.....]
From HJ Eysenck, Genius (Cambridge University Press, 1995) pp. 147-152.
Nowadays with the internet it is vastly easier to research things than it was back in the 1980s and 90s. I have now learnt that we did indeed have a rat-like prehuman ancestor, for 163 million years! As indicated in this video of your granny (which be warned is rather 'exciting' by the way):
same as at:
P.S.: The palaeontologists have not presented a very accurate image of the rat-like behaviour here. Just watch any squirrel or bird (in the wild) to see what I actually had in mind, and which surely would have applied as a defence against dinosaurs.
Meanwhile, in this charming video, eight-year-old Anthony seeks to describe his (and others') stimming (by which he basically means handflapping episodes). Note that he emphasises that it is liable to involve getting up and moving forward, which rather agrees with my theory's explanation of the handflapping as an atavism of the rat-like behaviour of our ancestors, as per Purgatorius video above. The point being that this shows some remaining trace of (hind) legs movements and forward movements as per the original function of the hypothesised innatons. Note in my 1993-published paper my explicit assumption that the handflapping did not have any related leg movements (because I was only going on the information I had at that time).
I should add that Anthony's attempted simulation of hand-movements does not correspond very well with actual videos of handflapping, which do indeed look suggestive of the rats' sprinting movements. For instance you can see (at 1.56) in this video of the Minamata disaster a more typical example of autistic handflapping, in this case seemingly caused by the mercury from the Minamata pollution (so best pretend you've not noticed it if you work for the FDA, CDC, NHS etc). And immediate before that you can see a cat doing something remarkably similar.