The study from the Journal of Research Into Personality isn't going to make the UC Berkeley professor who published it any friends on the right. Similar conclusions a few years ago from another academic saw him excoriated on right-wing blogs, and even led to a Congressional investigation into his research funding. But the new results are worth a look. In the 1960s Jack Block and his wife and fellow professor Jeanne Block (now deceased) began tracking more than 100 nursery school kids as part of a general study of personality. The kids' personalities were rated at the time by teachers and assistants who had known them for months. There's no reason to think political bias skewed the ratings — the investigators were not looking at political orientation back then. Even if they had been, it's unlikely that 3- and 4-year-olds would have had much idea about their political leanings.

A few decades later, Block followed up with more surveys, looking again at personality, and this time at politics, too. The whiny kids tended to grow up conservative, and turned into rigid young adults who hewed closely to traditional gender roles and were uncomfortable with ambiguity. The confident kids turned out liberal and were still hanging loose, turning into bright, non-conforming adults with wide interests. The girls were still outgoing, but the young men tended to turn a little introspective.

Block admits in his paper that liberal Berkeley is not representative of the whole country. But within his sample, he says, the results hold. He reasons that insecure kids look for the reassurance provided by tradition and authority, and find it in conservative politics. The more confident kids are eager to explore alternatives to the way things are, and find liberal politics more congenial. In a society that values self-confidence and out-goingness, it's a mostly flattering picture for liberals. It also runs contrary to the American stereotype of wimpy liberals and strong conservatives.

Of course, if you're studying the psychology of politics, you shouldn't be surprised to get a political reaction. Similar work by John T. Jost of Stanford and colleagues in 2003 drew a political backlash. The researchers reviewed 44 years worth of studies into the psychology of conservatism, and concluded that people who are dogmatic, fearful, intolerant of ambiguity and uncertainty, and who crave order and structure are more likely to gravitate to conservatism. Critics branded it the "conservatives are crazy" study and accused the authors of a political bias. Jost welcomed the new study, saying it lends support to his conclusions.