Uncommon Knowledge

What pacifiers do to boys

And other surprising insights from the social sciences

Alli Arnold for The Boston Globe

Parent alert: Pacifiers may be harmful to your sons’ emotional aptitude. Researchers have noted that the ability to mimic facial expressions helps us understand the emotions of others. Now, a new study of French and American youth has found that boys (but not girls) who spent more of their early years using pacifiers during the day—thereby limiting facial expressiveness—grew up to have less emotional aptitude, including less ability to mimic facial expressions and understand others’ perspectives. Thumb-sucking was not associated with reduced emotional aptitude.

Niedenthal, P. et al., “Negative Relations between Pacifier Use and Emotional Competence,” Basic and Applied Social Psychology (September/October 2012).

Do sweeteners boost self-control?

Self-control is generally thought to be a limited resource; studies have shown that it’s depleted by exertion, like muscle power. But a team of researchers is challenging the “energy model” of self-control: In new research, they found no evidence that depletion of self-control corresponded to blood sugar levels. Even more surprising, they found that simply rinsing one’s mouth with a sugar solution negated the depletion of self-control on both physical and cognitive tasks compared to rinsing one’s mouth with an artificial-sweetener solution. This was true even though subjects didn’t actually ingest the solution and couldn’t tell exactly what was in it. Therefore, the taste of sugar seems to be subconsciously enabling self-control.

Molden, D. et al., “Motivational Versus Metabolic Effects of Carbohydrates on Self-Control,” Psychological Science (forthcoming).

Improve your judgment with magnets


Most of us are notoriously stubborn in our political beliefs, embracing ideologically consistent information while discounting information that contradicts our beliefs. A new study suggests that this bias originates in a particular part of our brains—and that it’s not that hard to disable. Researchers applied transcranial magnetic stimulation to the inferior frontal gyrus for 40 seconds. In other words, they placed a coil that generates a fluctuating electromagnetic field over part of the frontal lobe. Five minutes after this procedure, subjects were asked to estimate the probabilities of various bad things happening to them and were then told the actual probabilities. When they were later asked for estimates a second time, subjects who had received magnetic stimulation to the left inferior frontal gyrus were equally responsive in updating their estimates to bad news (odds worse than expected) and good news (odds better than expected), while everyone else was biased towards the good news.

Sharot, T. et al., “Selectively Altering Belief Formation in the Human Brain,” Proceedings of the National Academy of Sciences (forthcoming).

Less status, more attraction to bling

Research has shown that conspicuous consumption is more common among racial minorities, as a way to compensate for lower status. New research shows that you don’t even have to be a minority to experience this effect—you just have to put yourself in those shoes. Not only did blacks with stronger racial identification feel more positively about high-status products, but so did whites who wrote a story imagining themselves to be black. In addition, whites who wrote a story imagining themselves to be janitors were more positive about high-status products than whites who imagined themselves to be brain surgeons.

Mazzocco, C. et al., “Direct and Vicarious Conspicuous Consumption: Identification with Low-Status Groups Increases the Desire for High-Status Goods,” Journal of Consumer Psychology (October 2012).

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