Who Did It?

Before patting yourself on the back for resisting that cookie or kicking yourself for giving in to temptation, look around. A new University of Georgia study has revealed that self-control -- or the lack thereof -- is contagious.

In a just-published series of studies involving hundreds of volunteers, researchers have found that watching or even thinking about someone with good self-control makes others more likely exert self-control. The researchers found that the opposite holds, too, so that people with bad self-control influence others negatively. The effect is so powerful, in fact, that seeing the name of someone with good or bad self-control flashing on a screen for just 10 milliseconds changed the behavior of volunteers.

"The take home message of this study is that picking social influences that are positive can improve your self-control," said lead author Michelle vanDellen, a visiting assistant professor in the UGA department of psychology. "And by exhibiting self-control, you're helping others around you do the same."

People tend to mimic the behavior of those around them, and characteristics such as smoking, drug use and obesity tend to spread through social networks. But vanDellen's study is thought to be the first to show that self-control is contagious across behaviors. That means that thinking about someone who exercises self-control by regularly exercising, for example, can make your more likely to stick with your financial goals, career goals or anything else that takes self-control on your part.

VanDellen's findings, which are published in the early online edition of the journal Personality and Social Psychology Bulletin, are the result of five separate studies conducted over two years with study co-author Rick Hoyle at Duke University.

In the first study, the researchers randomly assigned 36 volunteers to think about a friend with either good or bad self-control. Those that thought about a friend with good self-control persisted longer on a handgrip task commonly used to measure self-control, while the opposite held true for those who were asked to think about a friend with bad self-control.

In the second study, 71 volunteers watched others exert self-control by choosing a carrot from a plate in front of them instead of a cookie from a nearby plate, while others watched people eat the cookies instead of the carrots. The volunteers had no interaction with the tasters other than watching them, yet their performance was altered on a later test of self-control depending on who they were randomly assigned to watch.

In the third study, 42 volunteers were randomly assigned to list friends with both good and bad self-control. As they were completing a computerized test designed to measure self-control, the computer screen would flash the names for 10 milliseconds -- too fast to be read but enough to subliminally bring the names to mind. Those who were primed with the name of a friend with good self-control did better, while those primed with friends with bad self-control did worse.

In a fourth study, vanDellen randomly assigned 112 volunteers to write about a friend with good self-control, bad self-control or -- for a control group -- a friend who is moderately extroverted. On a later test of self-control, those who wrote about friends with good self-control did the best, while those who wrote about friends with bad self-control did the worst. The control group, those who wrote about a moderately extroverted friend, scored between the other two groups.

In the fifth study of 117 volunteers, the researchers found that those who were randomly assigned to write about friends with good self-control were faster than the other groups at identifying words related to self-control, such as achieve, discipline and effort. VanDellen said this finding suggests that self-control is contagious because being exposed to people with either good or bad self-control influences how accessible thoughts about self-control are.

VanDellen said the magnitude of the influence might be significant enough to be the difference between eating an extra cookie at a party or not, or deciding to go to the gym despite a long day at work. The effect isn't so strong that it absolves people of accountability for their actions, she explained, but it is a nudge toward or away from temptation.

"This isn't an excuse for blaming other people for our failures," vanDellen said. "Yes, I'm getting nudged, but it's not like my friend is taking the cookie and feeding it to me; the decision is ultimately mine."