I've spent the last 20 minutes or so digging and haven't found much (though I haven't read the book linked).
The most interesting paper I've found is this one from 1990 called The Biological Bases of extraversion: psychophysiological evidence [1]; which discusses a hypothesis by Sybil Eysenck from 1969.
Essentially, extraversion and introversion are first observed to be personality traits that can be passed genetically. Eysenck's hypothesis was that introverts were more sensitive to stimulation in the reticular activating system. Attempts to confirm this hypothesis have met with mixed success. Eysanck also came up with a personality inventory, similar to the popular MBTI and the "Big Five" inventory used by psychologists.
I haven't yet found anything particularly solid that confirms the connection between those physiological traits and the personality as defined by the Eysanck Questionnaire. Every other paper I have found so far begins by using the Eysanck Questionnaire to sort people into Introverts and Extraverts and does some other tests.
The most interesting paper I've found is this one from 1990 called The Biological Bases of extraversion: psychophysiological evidence [1]; which discusses a hypothesis by Sybil Eysenck from 1969.
Essentially, extraversion and introversion are first observed to be personality traits that can be passed genetically. Eysenck's hypothesis was that introverts were more sensitive to stimulation in the reticular activating system. Attempts to confirm this hypothesis have met with mixed success. Eysanck also came up with a personality inventory, similar to the popular MBTI and the "Big Five" inventory used by psychologists.
I haven't yet found anything particularly solid that confirms the connection between those physiological traits and the personality as defined by the Eysanck Questionnaire. Every other paper I have found so far begins by using the Eysanck Questionnaire to sort people into Introverts and Extraverts and does some other tests.
[1] http://www.ncbi.nlm.nih.gov.ezp-prod1.hul.harvard.edu/pubmed...