Describing human personalities as a mixture of four ingredients is a centuries old concept.  In Ned Herrmann’s work on personalities, he uses a model of quadrants of the brain, derived from the idea that the brain has a left and right neocortex and limbic system. Taking this to its logical conclusion, larger imbalances in usage could theoretically cause larger differences in behavior. This document discusses evidence that this type of imbalanced use of four parts of the brain could be the source of the kind of focused intelligence that creates plays, monuments and scientific theories, and that it could also create a vulnerability to learning and mental disorders, with autism at the more unbalanced end of that spectrum.

This part of the document argues that it is reasonable to believe that focused intelligence is created in the brain by overdeveloping some parts of the brain and leaving other parts underdeveloped.  This trade-off in abilities would explain the paradox that intelligence is associated with social problems and disorders of many kinds.  It is also consistent with the association in time of trends in increasing IQ’s and increasing number of people with disorders.  

This part of the document looks at how this four-part model is just complex enough to explain personality, the positive aspects of disorders, the overlapping nature of diagnoses, and the large number of described disorders with their gradient of symptoms.

This part of the document shows how this model could explain why people with autism are similar in broad ways, but differ in so many specific ways.  It could also explain some quirky aspects of autism such as why children with regressive autism are better babblers than other babies, and how someone with autism who uses facilitated communication could be described as a drama queen.

A listing of English-language biographies of people on the autistic spectrum – publishing dates 1964-2005.  These biographies were used in the author’s research on the extremes of autism.

This part of the document discusses the background of the author that led to this work, and research done by the author to test this theory.  Contemporary autistic biographies were examined for extremes in abilities.  Literature on the location of brain functions was examined to find the most easily recognizable markers to suggest strength of brain areas. This research suggests that classic autistic symptoms may be caused by strengths in using the left limbic system and right neocortex, and weak ability to use the other quadrants.

This part of the document discusses the long history of theories that include the idea of imbalances causing disorders, including Hippocrates and Geschwind.  It discusses how one brain hemisphere can inhibit the other side from taking over functions; this would explain why we shouldn’t expect plasticity of the brain to repair imbalances.  It also discusses how imbalanced development of the brain might occur, such as through the heterochronic process of neotony.