Footnotes

• ↵* High functioning autism (HFA) can be thought as within one standard deviation of population mean IQ (that is, IQ of 85 or above); medium functioning autism (MFA) can be thought of as between one and three standard deviations below the population mean (that is, IQ of 55–84). Low functioning autism (LFA) can be thought of below this (that is, IQ of 54 or below).

• ↵† This may help to explain why videos like Thomas the Tank Engine are favourites for many children with autism: there is no agentive change and almost all the non-agentive change is mechanical and linear, with close to 100% lawfulness.

• ↵†† I am indebted to Nigel Goldenfeld for suggesting this connection between hyper-systemising and IQ.

• ↵‡ Reduced generalisation is seen as a consequence of hyper-systemising. Systemising presumes that one does not generalise from one system to another until one has enough information that the rules of system A are identical to those of system B. Good generalisation may be a feature of average or poor systemisers, while “reduced” generalisation can be seen as a feature of hyper-systemising.

• ↵‡‡ Mind blindness in this model (see fig 1) is seen as arising from twin abnormalities: the SM being set too high, such that complex systems such as the social world are hard to predict via systemising; and atypical development of empathising mechanisms^14,1516 that in the normal case make it possible to make sense of the social world via an non-SM route.

• Competing interests: none declared

• Portions of this paper are taken from elsewhere. Reproduced with kind permission from Elsevier (Neuropsychopharmacology and Biological Psychiatry, in press[46])