Sitting in a hard chair can literally turn someone into a hardass. Holding a heavy clipboard leads to weighty decisions. Rubbing rough surfaces makes us prickly. So found researchers studying the interaction between physical touch and social cognition.

The experiments included would-be car buyers who, when seated in a cushy chair, were less likely to drive a stiff bargain. The findings don't just suggest tricks for salesman, but may illuminate how our brains develop.

"The way people understand the world is through physical experiences. The first sense they develop is touch," said study co-author Josh Ackerman, a Massachusetts Institute of Technology psychologist. As they grow up, those physical experiences shape how people conceptualize abstract, social experience, he said. "Later on, you can do what we did – trigger different physical experiences, and produce changes in people's thoughts."

Published June 24 in Science, the study is the latest addition to a booming field of embodied cognition, which over the last decade has scientifically eroded the notion that mind and body are distinctly separate.

Other studies have shown that kids are better at math when using their hands while thinking. Actors recall lines more easily while moving. People tend towards generosity after holding a warm cup of coffee, and are more callous after holding a cold drink.

The drink temperature study was co-authored by Yale University psychologist John Bargh, also a co-author of the latest paper. His group is especially interested in touch, which is one of the first senses to develop.

Other research shows that the brain doesn't always have different structures for different functions, but often uses the same systems in a variety of ways. And given the importance of touch, it's easy for developing brains to use tactile associations – heaviness requires effort, roughness leads to friction, hard objects are inflexible – in understanding social situations.

"Those connections that people have, between physical experience and mental understanding, don't ever disappear," said Ackerman.

To test the connection, the researchers conducted a variety of experiments simulating real-world social interactions. In one, test participants played the part of employers interviewing job applicants. When holding a heavy clipboard, they were more likely to consider candidates to be serious, and thought of their own judgements as especially important.

In another test, passerby asked to complete surveys on government funding of social programs were more likely to support increases while holding heavy clipboards. The problems seemed more significant.

After hearing stories about an ambiguous social interaction, test participants tended to consider it uncoordinated and harsh if they'd just handled a rough-surfaced jigsaw puzzle. After assembling a smooth puzzle, those ambiguous stories didn't seem so awkward.

Test subjects who touched a block of wood subsequently judged job applicants to be more strict in character than when they'd touched a blanked. And in the car negotiations, people sitting in stiff chairs rather than soft held out for an extra $350 price cut.

"The tactile sensation is extremely important early in development. The idea that other associations would be built on that makes intuitive sense," said Franklin & Marshall College psychologist Michael Anderson, who was not involved in the study. "Brain regions that may initially have been dedicated to one particular task, turn out ot contribute to multiple tasks."

It's not only people curious about brain development who will be interested in the findings. Manipulations "used in the studies might have important implications for a host of social situations such as job interviews, buyer/seller interactions, and the collection of signatures for petitions," said Gettysburg University psychologist Brian Meier.

For those fearing exploitation by marketers, Ackerman noted that tactile suggestion's effects diminish when people pay attention. "It's when you're distracted, thinking in a shallow fashion, that you get hit by these cues," he said.

The researchers want to further study how tactile-social interactions form during infancy and adolescence, and whether certain types of people are more susceptible than others. They're also curious whether tactility affects hormone balances and, in the short term, personality type.

Ackerman said the connection isn't one-way. "Once you have the connections, the process works both ways," he said. "There is some evidence that you can change people's sensations by changing their thoughts."

Image: Taber Andrew Bain/Flickr.

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Citation: "Incidental Haptic Sensations Influence Social Judgments and Decisions." By J.M. Ackerman, C.C. Nocera, J.A. Bargh. Science, Volume 328 No. 5987, June 22, 2010.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.