You don’t just need your eyes to think of the name of a tool; your hands get involved, too. A new study finds that people are slower to identify a picture of a tool if its handle is pointed toward a hand that is busy squeezing a ball.
Brain imaging studies have shown that when you identify a tool by name, the part of your brain that’s involved in manipulating the tool also turns on. Jessica K. Witt, of Purdue University, heard about some of this research and wanted to know whether it’s possible to slow down the process of coming up with the name by making the hands busy. “We said, ‘shouldn’t there be some behavioral consequences?’” She cowrote the study with David Kemmerer of Purdue, Sally A. Linkenauger of the University of Virginia, and Jody Culham of the University of Western Ontario.
In one experiment, each volunteer sat in front of a computer, squeezing a foam ball in one hand. They watched the screen while pictures appeared; each one showed either a tool or an animal. The participant was then supposed to name the tool or animal. People were generally slower at naming a tool if its handle was oriented toward the occupied hand. (They had no such problem with animals.)
The results suggest that keeping the hand which was closer to the tool’s handle busy interfered with people’s ability to think about the tool and retrieve its name. The research is published in Psychological Science, a journal of the Association for Psychological Science.
“Most people think of mental processes as being these separate independent processes,” says Witt. You have a part of the brain for semantics, like naming a tool, and then a different part of the brain for action, like configuring your hand so it can reach out and grab the tool. This work and other studies in the relatively new field of embodied cognition suggest that “these things are not so independent, but rather they’re integrated.”