Thursday, August 12, 2010

Is Personality a Myth?

A major study was just published describing a search for genetic correlates to personality; 5,000 Australian adults were given Myers-Briggs-style personality inventory tests, and then their DNA was searched for genes that might correlate with personality type. The study found no relationship whatsoever between any trait and any genetic marker. Jonah Lehrer thinks this is more evidence that "personality" as conventionally measured does not exist. He explains:
There has been a longstanding debate among psychologists about the proper way to measure and define human personality. On the one hand, there are plenty of researchers and clinicians who endorse tests like the Myers-Briggs Type Indicator (MBTI), which seeks to categorize people based on a series of supposedly innate personality dichotomies. (You’ve probably taken this test, and been given a summary in capital letters that describes your tendencies towards extraversion, intuition, judgement, etc.) On the other hand, there’s a camp of scientists which argues that these vague categories are mostly meaningless, and that asking people a few dozen multiple choice questions is a terrible way to summarize the soul. Walter Mischel (who I wrote about here, in the New Yorker) is one of these scientists. In 1958, while a young researcher at Harvard, he was asked to develop a survey course on “personality assessment.” Mischel quickly concluded that, while prevailing theories held personality traits to be broadly consistent – a shy person was always shy – the available data didn’t back this up. In fact, Mischel soon concluded that human personality, at least as it was then conceived, couldn’t be reliably assessed at all. A few years later, he was hired as a consultant on a personality assessment initiated by the Peace Corps. Early Peace Corps volunteers had sparked several embarrassing international incidents—one mailed a postcard on which she expressed disgust at the sanitary habits of her host country—so the Kennedy Administration wanted a screening process to eliminate people unsuited for foreign assignments. Volunteers were tested for standard personality traits, and Mischel compared the results with ratings of how well the volunteers performed in the field. He found no correlation; the time-consuming tests predicted nothing. At this point, Mischel realized that the problem wasn’t the tests—it was their premise. Psychologists had spent decades searching for traits that exist independently of circumstance, but what if personality can’t be separated from context?
I once took a Myers-Briggs-style test designed to help people choose careers. I scored introverted, as I always do on such tests, and the test advised me against any career involving teaching or public speaking. But I love to teach, and speaking in public is one of my favorite parts of my job. In other situations I am by nature quite shy. I have trained myself over the years to become more comfortable in parties and similar social situations, but my instinct is to avoid them at all costs and hide in a corner if I must attend. I still find it painful to call a stranger on the phone. So I am sympathetic to the notion that some traits are situational. I suspect, though, that the complete lack of fit between genetic testing and personality testing is a sign of the crudeness of both these sciences at the present time, not proof that personality does not exist.


Thomas said...

Is the test you took a failure because personality doesn't exist, or because the mapping from personality to jobs was a failure? I've done a lot of amateur theater, and a fair number of actors are introverted offstage.

What the genetic study shows is that there aren't obvious genetic markers for things like introversion/extroversion, but that doesn't mean they aren't valid personality traits. There is always the nurture side of the equation.

John said...

Lehrer's point is that a trait like introversion does not exist in a personality, it exists in how people respond to certain situations. To put it another way, you can't abstract a person from his or her circumstances and say, "no matter where he goes or what he faces, he will always be the same man." The kind of person we are depends, so the argument goes, on the circumstances we are in.

Unknown said...

As I read it, the quoted passage does not seem to be saying that personality is a myth, only that the current methods for assessing it are inadequate.

A lot of this sounds like it might be about wrongheaded a priori academic discipline requirements. I would be surprised if there isn't some rule out there that says you have to assume personality traits are constant (shy people always act shy and will always be shy), or you're not doing Jones Test-Based Experimental Psychology (JTBEP (tm)), or some such.

It strikes me that any theory of human behavior and psychology that doesn't allow for complexity, contingency, changeability, and similar things is obviously flawed. (Oops, another rigid academic rule. Oh, well.)

We've also barely begun to appreciate the complex interactions between genes, physical environment, nurture, etc. A person with 20 specific genes, who grows up with a water supply with 16.5 parts per million of ionic lithium but who then moves to a city with no lithium in the water, with 2 older siblings and one dead parent, and raised in a lax educational environment with 10 parts per billion of diesel exhaust, will be 7.556% more likely to be shy at parties but not on stage, except during the most active sunspot periods, etc., etc., etc.

Katya said...

This is one of those "parents of identical twins will roll their eyes at the idea that personality is determined by genetics" moments.

Okay, I do accept that certain characteristics are genetic (nervousness is said to be one). But personality is not the same as characteristics.