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August 14, 2006

Psychology professor intrigued by the roots of human cognition

By Jennifer McNulty

Cognitive psychologist Margaret Wilson is drawn to the big questions of human psychology: What makes human cognition different? What is the evolutionary story of human cognition?

Photo: Margaret Wilson
Margaret Wilson

“I would like to be considered a theoretical psychologist, just like there are theoretical physicists,” said Wilson, an assistant professor of psychology whose research publications are interspersed with numerous theoretical papers. “Data is important, but to me it is even more important to back up and look at the big picture and try to integrate it into a single, coherent story.”

The part of that “big picture” that most captivates Wilson is the fundamental question of what enabled prehumans to break away from their primate ancestors and surge to the front of the pack in their ability to think, reason, and use language. It’s a multidisciplinary mystery, and Wilson has a hunch that the brain’s capacity to imitate is a key factor that sets humans apart.

“A lot of what looks like imitation in animals isn’t,” said Wilson. “People think chimpanzees can imitate, because they can learn about objects from each other, but they’re not actually copying actions of the body.”

Wilson suspects the ability to imitate could be the key that led to a cascade of other human cognitive abilities, including the ability to make analogies and do abstract representation. Over the past decade or so, she has focused her research on short-term memory--the ability to hold information temporarily in mind without interruption.

“I believe short-term memory is covert imitation,” she said. “You’re imagining imitating the stimulus. I think of it as mapping. We do it effortlessly.”

Wilson’s latest lab findings clear up a long-held misunderstanding about the way memory functions by establishing that short-term memory is equal among deaf people who use American Sign Language and hearing people who rely on the spoken word.

Previous studies suggested that signers have smaller short-term memory capacity, but Wilson reports in the August issue of the journal Psychological Science that differences disappear when subjects are given precisely matched sets of ASL and spoken stimuli. Previous studies compared common English words and ASL signs, or signed letters and spoken numbers, without controlling for the amount of time it takes to articulate the different stimuli or the fact that numbers are problematic in comparative laboratory experiments because they have a unique superiority in short-term memory.

Researchers studying short-term memory have long believed that spoken language is unique, but Wilson’s findings erode that tenet and suggest that universal principles are at work. “Short-term memory isn’t a single dedicated mechanism, it’s a principle, and it works the same whether it’s the mouth or the hand that’s moving,” she said. “There does not appear to be a dedicated mechanism for verbal speech.”

That insight bolsters Wilson’s eagerness to explore the role of imitation in different laboratory protocols. Wilson, who teaches a course on the evolution of cognition, is also investigating how humans perceive the body movements of others and the role of imitation in perception.

“Our perceptions of others’ bodies is changed by what we’re doing with our own bodies, because information flows from the motor system to the perceptual system,” she said. “Perceiving stimuli that can be imitated is qualitatively different from perceiving stimuli that can’t be imitated.”

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