Rough stuff. Volunteers who played with a sandpaper-covered puzzle judged social interactions as more difficult and hostile than did those who assembled a smooth puzzle.


Sense of Touch Colors Our View of the World

The next time you absently palm that paperweight on your desk, ponder this: The physical characteristics of the objects you touch can influence how you perceive the world. Holding a heavy clipboard, for example, may lead you to view a job applicant as more serious. And, according to a new study, running your hand over sandpaper may make you view social interactions as more hostile and competitive.

The idea that our physical environment can influence our thinking—a concept called "embodied cognition"—is not new. In 2008, researchers reported that simply holding a warm cup of coffee prompts us to view others as emotionally warmer. Last year, a separate group found that holding a heavy clipboard makes us perceive social-justice issues as more important: In a theoretical scenario, volunteers holding a heavy clipboard were more likely to support a student grievance with a university committee than were those holding a light clipboard.

In the new study, Joshua Ackerman, a psychologist at the Massachusetts Institute of Technology in Cambridge, and colleagues looked at the impact of texture and hardness on how we perceive the world. In one experiment, the team asked volunteers to put together a puzzle, giving half of them smooth pieces and half of them pieces covered in sandpaper. The subjects then read a paragraph describing an interaction between two people that included an exchange of sharp words and some kidding around. Participants who put together the rough puzzle ranked the interaction as more adversarial and competitive than did those who put together the smooth puzzle.

The association between physical roughness and mental roughness also influenced people's behaviors. In another experiment, the researchers gave each subject 10 lottery tickets and asked them to offer up some of their tickets to a second participant. If this hypothetical participant accepted their offer, the duo would keep the lottery tickets. If he or she rejected the offer, both would lose the tickets. People who assembled the rough puzzle tended to give away more tickets, suggesting that they anticipated that the interaction would be difficult. "Roughness is really associated with friction," says Ackerman. So it makes sense, he says, that people who handle rough objects will also perceive the world to be more difficult and less cooperative.

The link between physical sensations and behavior appears to hold even when the person passively touches an object. When the researchers seated participants in hard or soft chairs and asked them to imagine haggling with a dealer over the price of a new car, they found that the people in hard wooden chairs were less willing to negotiate. The team reports its findings in tomorrow's issue of Science.

Ackerman and his colleagues posit that the link between physical sensations and our perceptions arise during development. Babies learn by touching. As they grow, they may use concrete physical sensations as a "scaffold" in order to grasp more abstract concepts, the researchers explain. Eventually, the physical and the abstract become linked. Metaphors, such as a "rough" day and a "warm" smile, reflect the "real underlying ties between physical experience and mental understanding," Ackerman says.

The findings communicate "very nicely" the importance of touch, says Chen-Bo Zhong, a psychologist at the University of Toronto in Canada. Beyond that, Zhong says, the study suggests that we can make better decisions by recognizing these physical signals that are "outside of our conscious awareness."

Indeed, previous studies and Ackerman's own unpublished work suggest that these unconscious effects all but disappear once the individual pays attention to them. "So if people are thinking these things through, they're going to make better decisions," he says. The danger is that "people are usually not thinking things through."

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