An experiment that Sigmund Freud could never have imagined 100 years ago may help lend scientific support for one of his key theories, and help connect it with current neuroscience.
Today at the 101st Annual Meeting of the American Psychoanalytic Association, a University of Michigan professor who has spent decades applying scientific methods to the study of psychoanalysis will present new data supporting a causal link between the psychoanalytic concept known as unconscious conflict, and the conscious symptoms experienced by people with anxiety disorders such as phobias.
Howard Shevrin, Ph.D., emeritus professor of psychology in the U-M Medical School's Department of Psychiatry, will present data from experiments performed in U-M's Ormond and Hazel Hunt Laboratory.
The research involved 11 people with anxiety disorders who each received a series of psychoanalytically oriented diagnostic sessions conducted by a psychoanalyst.
From these interviews the psychoanalysts inferred what underlying unconscious conflict might be causing the person's anxiety disorder. Words capturing the nature of the unconscious conflict were then selected from the interviews and used as stimuli in the laboratory. They also selected words related to each patient's experience of anxiety disorder symptoms. Although these words differed from patient to patient, results showed that they functioned in the same way.
These verbal stimuli were presented subliminally at one thousandth of a second, and supraliminally at 30 milliseconds. A control category of stimuli was added that had no relationship to the unconscious conflict or anxiety symptom. While the stimuli were presented to the patients, scalp electrodes record the brain responses to them.
In a previous experiment Shevrin had demonstrated that time-frequency features, a type of brain activity, showed that patients grouped the unconscious conflict stimuli together only when they were presented subliminally. But the conscious symptom-related stimuli showed the reverse pattern – brain activity was better grouped together when patients viewed those words supraliminally.
"Only when the unconscious conflict words were presented unconsciously could the brain see them as connected," Shevrin notes. "What the analysts put together from the interview session made sense to the brain only unconsciously."
However, the experimental design in this first experiment did not allow for directly comparing the effect of the unconscious conflict stimuli on the conscious symptom stimuli.