This week's New Scientist (13 Sep 2003) features a story by Graham Lawton that investigates the emerging biological basis of personality. Researchers are finding gene expression patterns that influence behavioral traits.
There are many personality models, most of them with five traits. Psychologists now generally agree that all of them measure essentially the same characteristics. One leading version is the NEO Personality Inventory. Its five dimensions are neuroticism, extroversion, opennes to experience, agreeableness and conscientiousness. They're independent of each other - there's no correlation between the score you get for one vs. the score you get for another. Klaus-Peter Lesch at the University of Wurzburg has reported finding a gene variant that correlates with neuroticism, and and Israeli team has found a similar link to extroversion.
I found a version of the NEO-PI on the web prepared by John A. Johnson, the IPIP-NEO. I took the short version, and the results came as little surprise. (That's somewhat to be expected, since it's testing my self-perception. I haven't yet done the control where I ask someone else to evaluate me.) For the record:
Extroversion: Low. Introverted, reserved, quiet. Enjoys solitude and solitary activities. Socializing tends to be restricted to a few close friends.
Agreeableness: High. Strong interest in others' needs and well-being. Pleasant, sympathetic, cooperative.
Conscientiousness: High. Sets clear goals and pursues them with determination. Regarded as reliable and hard-working.
Neuroticism: Low. Calm, composed, unflappable. (I do, however, have a high Depression sub-score. This seems to be a family trait - here come those genes!)
Openness to Experience: High. Enjoys novelty, variety, change. Curious, imaginative, creative.
This was useful data for me. I've always been confused by the fact that I am perceived to be sociable, while in fact I prefer solitude. By this model, that's because I score high on agreeableness, but low on extroversion.
The other key insight is that I will not be happy in a leadership role where I have to spend a lot of time with people - even though my amiability and calmness might lead people to believe that I'd be a decent leader. In fact, I'd be lousy at the kind of leadership that requires forcing through tough decisions - one needs low agreeableness for that.