The University Record, June 11, 1997

Study shows unconscious defenses exist

By Diane Swanbrow
News and Information Services

A U-M study provides strong scientific evidence for the existence of one of the key cornerstones of psychoanalysis: unconscious defense mechanisms.

The study, conducted by researchers Michael Snodgrass and Howard Shevrin, relies on an ingenious experiment using subliminal perception.

Part of a growing body of work using scientific methods and modern technology to illuminate one of the murkiest and most controversial aspects of the mind---the unconscious---the study was presented May 25 in Washington, D.C., at the annual meeting of the American Psychological Society. It also will be presented this month at the meeting of the Association for the Scientific Study of Consciousness.

For the study, Snodgrass, a researcher at the Medical School, and Shevrin, professor of psychology, tested 100 subjects using a tachistoscope, a device that flashes words or images at different speeds. Shevrin directs the U-M Hunt Laboratory, where the experiments are part of a program of research on unconscious processes.

Subjects were asked to identify which of four words was being flashed at random at a speed below the threshold of conscious perception.

During a previous practice period, each subject tried two different strategies: 1) say the first of the four words that "pops" into mind, and 2) look carefully for any clues, such as letter fragments or shadows, before responding. After trying out both strategies, subjects were asked which strategy they preferred. Then they completed experimental trials.

Researchers compared the accuracy of "lookers" vs. "poppers" while they were using their preferred strategy and while they were using the strategy they felt less comfortable with.

By chance, all subjects would be expected to identify the correct word 25 percent of the time. But when lookers were required to pop, they performed significantly worse than chance.

The results not only reaffirm the existence of subliminal perception but also show that unconscious perception can be unconsciously repressed or inhibited.

"The lookers were uncomfortable relinquishing conscious control, as the pop strategy required,"

Snodgrass says. "Thus they unconsciously inhibited the correct answers; they were systematically wrong.

"For many years, the existence of unconscious defense has been regarded as unproven," notes Snodgrass. "The inhibition effect may well provide a simple, easily replicable demonstration of this phenomenon."