Non _g_ psychometrics - status of genetic importance? biology?

[Nereid]

In the Questions on _g_ and intelligence thread (http://www.physicsforums.com/showthread.php?t=40190&page=1&pp=15) we have been discussing one branch of psychology (psychometrics), and one branch within that sub-discipline (intelligence).

In that thread, Mandrake quoted Jensen:Jensen: "The fact that _g_ is more strongly genetic than most other psychological variables is not really controversial among empirical researchers in this field. It is highly controversial only in the popular media. Just try to find any real controversy among the experts who know the research on this issue." Miele (2002) - Intelligence, Race, and Genetics: Conversations with Arthur R. Jensen - P. 79.This got me wondering, what is the status of all other psychological variables, wrt genetics? In particular, since psychometrics is much broader than just intelligence - it includes, for example, personality, aptitudes, interests, achievement, and proficiency - how far have psychologists got in terms of showing genetic bases for these (presumably) quantitatively characterised aspects?

Psychology is, of course, concerned with brains, albeit indirectly. With the recent advances in neuroscience, one might expect that the 'brain biology' basis for findings in psychology could be elucidated. Indeed, as this comment by Mandrake - wrt intelligence and _g_ - makes clear, intelligence psychometricians believe they have made just such connections:There are various models of how the brain processes information. Some of these can be diagramed and are shown in The _g_ Factor. There are also the sideline theories that have been advanced by Gardner and Sternberg.How widely are such brain models used by psychometricians studying, for example, personality? What different brain models do other psychologists use? How do these various models relate to what neuroscientists have found?

[marcus]

...This got me wondering, what is the status of all other psychological variables, wrt genetics?...

Like gypsies playing the violin!

Yes.

I wonder too.

have gypsies evolved a slight genetic-based statistical aptitude
for playing the violin

or pehaps they have taken it up because simply by accident they tend to be physically well suited for it?

perhaps in the fullness of time all these things will be revealed

[Tigers2B1]

Here's something I've posted elsewhere and will post it here - again - since this may be what you're asking ----

As this study of monozygotic twins reared apart indicates, personality seems to be strongly heritable for most traits. So, while this might have been turned into a political issue– (and it has been) the evidence is strong that more than our physical appearance is substantially affected by our genetic makeup. There are studies out there that support the conclusion that we are affected by our genes both on the inside and out. Considering this – it doesn't take much of an imagination to suspect that behavior might very well be, at least in some aspect, a product of evolution – rather than as some advocate – all socialized into the individual.

http://www.mugu.com/cgi-bin/Upstream/Issues/psychology/IQ/bouchard-twins.html

Sources of human psychological differences: the Minnesota Study of Twins Reared Apart.

Bouchard TJ Jr, Lykken DT, McGue M, Segal NL, Tellegen A.

Department of Psychology, University of Minnesota, Minneapolis 55455.

Since 1979, a continuing study of monozygotic and dizygotic twins, separated in infancy and reared apart, has subjected more than 100 sets of reared-apart twins or triplets to a week of intensive psychological and physiological assessment... On multiple measures of personality and temperament, occupational and leisure-time interests, and social attitudes, monozygotic twins reared apart are about as similar as are monozygotic twins reared together. These findings extend and support those from numerous other twin, family, and adoption studies. It is a plausible hypothesis that genetic differences affect psychological differences largely indirectly, by influencing the effective environment of the developing child. This evidence for the strong heritability of most psychological traits, sensibly construed, does not detract from the value or importance of parenting, education, and other propaedeutic interventions.


…The study of these reared-apart twins has led to two general and seemingly remarkable conclusions concerning the sources of the psychological differences - behavioral variation - between people: (i) genetic factors exert a pronounced and pervasive influence on behavioral variability, and (ii) the effect of being reared in the same home is negligible for many psychological traits. These conclusions will not come as revelations to the many behavioral geneticists who have observed similar results and drawn similar conclusions [5]. This study and the broader behavioral genetic literature, nevertheless, challenge prevailing psychological theories on the origins of individual differences in ability, personality, interests, and social attitudes [6]…