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What brain mechanism causes loneliness?

Sunday, 15 February 2009

Credit: Jens Langner, Wikimedia commons

Social isolation affects how people behave as well as how their brains operate, a study at the University of Chicago shows.

The research, presented Sunday at a symposium, "Social Emotion and the Brain," at the annual meeting of the American Association for the Advancement of Science, is the first to use fMRI scans to study the connections between perceived social isolation (or loneliness) and activity in the brain. Combining fMRI scans with data relevant to social behavior is part of an emerging field examining brain mechanisms—an approach to psychology being pioneered at the University of Chicago.

Researchers found that the ventral striatum—a region of the brain associated with rewards—is much more activated in non-lonely people than in the lonely when they view pictures of people in pleasant settings. In contrast, the temporoparietal junction—a region associated with taking the perspective of another person—is much less activated among lonely than in the non-lonely when viewing pictures of people in unpleasant settings.

"Given their feelings of social isolation, lonely individuals may be left to find relative comfort in nonsocial rewards," said John Cacioppo, the Tiffany and Margaret Blake Professor in Psychology at the University. He spoke at the briefing along with Jean Decety, the Irving B. Harris Professor in Psychology and Psychiatry at the University.

The ventral striatum, which is critical to learning, is a key portion of the brain and is activated through primary rewards such as food and secondary rewards such as money. Social rewards and feelings of love also may activate the region.

Cacioppo, one of the nation's leading scholars on loneliness, has shown that loneliness undermines health and can be as detrimental as smoking. About one in five Americans experience loneliness, he said. Decety is one of the nation's leading researchers to use fMRI scans to explore empathy.

They were among five co-authors of a paper, In the Eye of the Beholder: Individual Differences in Perceived Social Isolation Predict Regional Brain Activation to Social Stimuli, published in the current issue of the Journal of Cognitive Neuroscience.