Descending to personalities

I've never really understood why descending to personalities meant beginning to hurl insults. Personality testing is certainly rich in potential insults; it's hard to make someone who scores very low on agreeableness and conscientiousness sound appealing. I suppose he might make an excellent highwayman.

Here is a little more detail, from a professor of psychology at UO, on the general acceptance of the Big 5 model:

McCrae and Costa’s (1985a,b,c; 1987) findings, like the cross-instrument convergence described above, show that the factor-analytic results from the lexical tradition converge surprisingly well with those from the questionnaire tradition. This convergence has led to a dramatic change in the acceptance of the five factors in the field. With regard to their empirical status, the findings accumulated since the mid-1980s show that the five factors replicate across different types of subjects, raters, and data sources, in both dictionary based and questionnaire-based studies. Indeed, even more skeptical reviewers were led to conclude that “Agreement among these descriptive studies with respect to what are the appropriate dimensions is impressive” (Revelle, 1987, p. 437; see also Briggs, 1989; McAdams, 1992; Pervin, 1994). The finding that it doesn’t matter whether Conscientiousness is measured with trait adjectives, short phrases, or questionnaire items suggests that the Big Five dimensions have the same conceptual status as other personality constructs. For example, Loehlin et al. (1998) found that all five factors show substantial and about equal heritabilities, regardless of whether they are measured with questionnaires or with adjective scales derived from the lexical approach.

Of course, the fact that Freudianism is still mucking up psychology (the quoted author even refers positively to Freud's concept of love) suggests that psychological consensus is not all that one might want.

Hoping, for the moment, that psychology isn't lost in fantasy again, there is that interesting remark about heritability. According to wikipedia, twin studies have shown these per-trait heritabilities:

Openness: 57%
Extraversion: 54%
Conscientiousness: 49%
Neuroticism: 48%
Agreeableness: 42%

Those are about as heritable as IQ. Obviously these all leave a great deal of room for environmental effects. Parents, at least traditional parents who care enough about their children to exercise authority, spend a lot of effort on controlling the environmental factors. I haven't known many people who sent their children to private schools, so this is only anecdotal, but controlling their children's environment had a substantial part in the decision. If, say, 57% of openness is heritable, and the remainder is split among school environment, neighborhood interactions, church, randomly acquired friends, and TV, then little of a child's personality conditioning can even be influenced strongly, let alone controlled, by parenting as such. By comparison, it's easy to see that marrying well vastly outweighs striving for a perfect environment. It also provides a good measure for determining what it means to marry well: good personality traits are irreplaceable and durable assets to give children, while good looks fade and money has a habit of getting lost and found across generations.

It's also interesting to think what might happen if the five factors are really capable of being inherited separately. (With S for stability instead of N:) A woman with a high A, high E, low C, low S, middle O married to a man with a middle A, low E, middle C, high S, and high O could produce, ab ovo, a middle A, low E, low C, low S, high O child who might be impulsively inquisitive and likeable past some reserve, but whose emotional stability was very likely to be disturbed in any social interaction, few of which would be sought out. Such a child might seem like an alien to both parents, with the mother baffled by seeming social retardation and the father astonished that a fellow bookworm could be so explosive and impulsive; the resulting adult might still be something as valuable as a high-energy academic like a field biologist. Coming up all trumps could be just as unsettling, as I think might have happened in my family, if it's the case that a middle A, low E, high C, high S, high O and a high A, middle E, middle C, low S, middle O yielded my youngest brother who is high A, middle-high E, high C, high S, high O, so that he gives the impression of having recently arrived from a more than usually holy and scholastic monastery.

Of course all of that takes a naive view of heritability (in reality these traits, if they have a genetic component, are spread across many genes with varying influence) and for the sake of argument disregards environment. Still it's interesting to think about the broad outlines of a personality being assembled from a mixture of parental elements, the way it's customary to talk about a child having his father's nose and his mother's eyes.