Uncommon Knowledge

Think you have self-control? Careful.

Surprising insights from the social sciences

(Wesley Bedrosian for The Boston Globe)
By Kevin Lewis
January 3, 2010

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One way to enhance self-control is to avoid tempting situations. The irony, according to a recent study, is that people who think they have more self-control allow themselves to get into more tempting situations and, as a result, are more likely to give in to temptation. For example, students who were made to feel fatigued were less confident in their ability to control fatigue and were less willing to put off studying for exams. Smokers who were led to believe that they had superior self-control were more willing to keep a proscribed cigarette in their proximity while watching the movie “Coffee and Cigarettes,” and, as a result, they were more likely to smoke it. Likewise, smokers who were trying to quit and who also felt they had high self-control were less likely to have abstained four months later, on account of not being diligent enough in avoiding temptation.

Nordgren, L. et al., “The Restraint Bias: How the Illusion of Self-Restraint Promotes Impulsive Behavior,” Psychological Science (December 2009).

Divided by color
Since the 2000 election, political analysts have consistently referred to Republican-leaning states as “red” and Democratic-leaning states as “blue.” Of course, states are not composed entirely of Republicans or Democrats, and, in fact, most states have a pretty even mix. Nevertheless, researchers wondered what effect the red-blue dichotomy might have on perceptions of political reality. People were shown electoral maps with a stark red-blue scheme, with a scheme where red and blue were mixed in proportion to the vote, or the same maps but with numeric data. People who saw the map with the stark red-blue scheme and without numeric data assumed that the nation was more divided, that there were greater differences on specific political issues, and that one’s vote was less likely to matter.

Rutchick, A. et al., “Seeing Red (and Blue): Effects of Electoral College Depictions on Political Group Perception,” Analyses of Social Issues and Public Policy (December 2009).

Do tattoos mean good genes?
Tattoos and unusual piercings carry the stereotype of nonconformity. Just ask yourself: How often do you see them on business managers or government officials? However, a new study from anthropologists in Poland suggests that, for men, tattoos and piercings are actually signals of biological quality. The researchers compared the body symmetry - specifically, measurements of the right and left hands - of people with tattoos and piercings to a similar group of people without tattoos and piercings. Symmetry has been established in previous research as a good indicator of biological quality (i.e., “good genes”). Men with tattoos and piercings were significantly more symmetrical than men without tattoos and piercings. The authors theorize that, given the pain and risk of infection from getting tattoos and piercings, only stronger men will get them.

Koziel, S. et al., “Tattoo and Piercing as Signals of Biological Quality,” Evolution and Human Behavior (forthcoming).

I’m hungry. You’re hot.
It’s said that you shouldn’t go grocery shopping on an empty stomach, because everything will look appetizing. According to researchers, you should also be careful about shopping for a mate on an empty stomach - hunger may affect your choice. College students were surveyed either before or after dinner about their preferences for an ideal mate. Hungry men (i.e., those surveyed before dinner) preferred heavier, taller, and older women, and these preferences were strengthened when the men were asked upfront about their hunger. Women’s preferences for physical traits were not significantly affected by hunger, but hungry women did prefer men with more mature (“strong, mature, independent, competent”) personalities. The authors theorize that the sensation of hunger, as a survival cue, prompts men to seek hardier females, and prompts women to seek more protective men.

Pettijohn, T. et al., “Hungry People Prefer More Mature Mates: A Field Test of the Environmental Security Hypothesis,” Journal of Social, Evolutionary, and Cultural Psychology (September 2009).

Unleashing the selfish brain
Self-control is one of the most important traits for success in life. Not only is it good for your health, but it’s good for your reputation. Someone who goes for the short-term win at the expense of others will probably lose much more in the long run. To get at the part of the brain responsible for this, Swiss researchers used a technique called low-frequency repetitive transcranial magnetic stimulation - where a coil that generates a fluctuating electromagnetic field is placed over part of the head - to selectively impair certain brain regions. After the procedure, people played a sharing game, such that being greedy in one round would lead to less generosity from others in subsequent rounds. After one particular part of the brain was impaired - the right dorsolateral prefrontal cortex - people were unable to stop themselves from being greedy in the moment, even though they knew intellectually that this would lead to a bad reputation.

Knoch, D. et al., “Disrupting the Prefrontal Cortex Diminishes the Human Ability to Build a Good Reputation,” Proceedings of the National Academy of Sciences (December 2009).

Kevin Lewis is an Ideas columnist. He can be reached at