The joys of social science

Every day, hundreds of thousands of scholars study human behavior. Every day, a few of their studies are bundled and distributed via e-mail by Kevin Lewis, who covers the social sciences for The Boston Globe and National Affairs. And every day, I file away these studies because I find them bizarrely interesting.

In this column, I'm going to try to summarize as many of these studies as space allows. No single study is dispositive, but I hope these summaries can spark some conversations:

Female mammals tend to avoid close male relatives during moments of peak fertility in order to avoid inbreeding. For the journal Psychological Science, Debra Lieberman, Elizabeth Pillsworth and Martie Haselton tracked young women's cellphone calls. They found that these women had fewer and shorter calls with their fathers during peak fertility days, but not with female relatives.

Classic research has suggested that the more people doubt their own beliefs the more, paradoxically, they are inclined to proselytize in favor of them. David Gal and Derek Rucker published a study in Psychological Science in which they presented some research subjects with evidence that undermined their core convictions. The subjects who were forced to confront the counterevidence went on to more forcefully advocate their original beliefs, thus confirming the earlier findings.

Physical contact improves team performance. For the journal Emotion, Michael Kraus, Cassey Huang and Dacher Keltner measured how frequently members of NBA teams touched each other. Teams that touched each other frequently early in the 2008-2009 season did better than teams that touched less frequently, even after accounting for player status, preseason expectations and early season performance.

According to John Gaski and Jeff Sagarin in the Journal of Neuroscience, Psychology and Economics, there is a surprisingly strong relationship between daylight saving time and lower SAT scores. No explanation was offered.

For an article in The Review of Economics and Statistics, Mark Duggan, Randi Hjalmarsson and Brian Jacob investigated whether gun shows increase crime rates. They identified 3,400 gun shows in Texas and California and looked at crime rates for the areas around the shows for the following month. They found no relationship between gun shows and crime in either state.

Self-control consumes glucose in the brain. For an article in the journal Aggressive Behavior, Nathan DeWall, Timothy Deckman, Matthew Gaillot and Brad Bushman found that research subjects who consumed a glucose beverage behaved less aggressively than subjects who drank a placebo beverage. They found an indirect relationship between diabetes (a disorder marked by low glucose levels) and low self-control. States with high diabetes rates also had high crime rates. Countries with a different condition that leads to low glucose levels had higher killing rates, both during wartime and during peacetime.

We tend to admire extroverted leaders. But Adam Grant, Fran-cesca Gino and David Hofmann have added a wrinkle to this bias in an article in The Academy of Management Journal. They found that extroverted leaders perform best when their employees are passive, but this effect is reversed when the employees are proactive. In these cases, the extroverted leaders are less receptive to their employees' initiatives.

Beautiful women should take up chess. Anna Dreber, Christer Gerdes and Patrik Gransmark wrote a Stockholm University working paper in which they found that male chess players pursue riskier strategies when they're facing attractive female opponents, even though the risk-taking didn't improve their performance.

People remember information that is hard to master. In a study for Cognition, Connor Diemand-Yauman, Daniel Oppenheimer and Erikka Vaughan found that information in hard-to-read fonts was better remembered than information transmitted in easier fonts.

Would you rather date someone who dumped his or her last partner or someone who was the dumpee? For an article in Evolutionary Psychology, Christine Stanik, Robert Kurzban and Phoebe Ellsworth found that men will give a woman a lower rating when they learn that she dumped her last boyfriend, perhaps fearing they will be next. But women rated men more highly when they learned that they had done the dumping, perhaps seeing it as a sign of desirability.

These studies remind us that we are strange, complicated creatures — deeply influenced by primordial biases and our current relationships. But you don't have to settle for my summaries of these kinds of studies. Go to the National Affairs website, where there are links to Kevin Lewis's daily batch of studies. A day without social science is like a day without sunshine.

David Brooks is a regular columnist for The New York Times.