Mood Linked To Cognitive Abilities

"To have the best mental performance and the most efficient pattern of brain activity, you need a match between the type of mood you are in and the type of task you are doing," said Jeremy Gray, Ph.D., a Research Scientist in the Psychology Department in Arts & Sciences and lead author of the study. "This is one of the first studies to really show that performance and brain activity are a product of an equal partnership or marriage between our emotional states and higher cognition."

Scheduled for publication March 19 in Proceedings of the National Academy of Sciences, the study is co-authored by Gray and Washington University colleagues Todd Braver, Ph.D., assistant professor of psychology in Arts & Sciences and director of the laboratory where the study was conducted, and Marcus Raichle, M.D., professor of radiology, neurology, anatomy and neurobiology in the School of Medicine.

"Our results suggest that emotion is not a second-class citizen in the world of the brain," Gray said. "The findings surprise people. Mild anxiety actually improved performance on some kinds of difficult tasks, but hurt performance on others. Being in a pleasant mood boosted some kinds of performance but impaired other kinds. To understand how a particular emotion or mood will influence performance, you have to take into account the type of task. Our results show that the brain takes it into account."

Using a sophisticated technique called functional magnetic resonance imaging (fMRI), Gray and colleagues recorded brain activity as people performed difficult cognitive tasks just after watching short, emotional videos. The lingering effects of the videos had remarkably specific influences on the levels of brain activity. A region of the prefrontal cortex was jointly influenced by a combination of mood state and cognitive task, but not by either one alone. Located just under the temples and slightly higher, near the corner of the forehead, this area had been previously thought to be critical for higher mental functions. However, the current work suggests that the region may actually be critical for integrating cognitive tasks together with emotional signals.

"The patterns of activity in this area suggested that it plays a regulatory role, because it responded to the changes in subjective difficulty imposed by the various emotion-cognition combinations," Braver said. "Our evidence for this is that the activity in this region was correlated with behavioral performance, such that stronger activity may have helped to reduce the influence that emotion had on modulating behavior.

"We believe that this is the first study to show that specific brain regions mediate these interactions between emotional states and cognition," Braver added. "Moreover, the findings seem to refute our common sense notions about these interactions--for example, that bad moods are always detrimental for cognition; good moods are always beneficial."

In the study, 14 college-aged men and women were shown a series of short video clips, which elicited one of three emotional states: pleasant, neutral or anxious. Pleasant moods were induced by viewing television comedies, such as "Candid Camera" (1985); and anxious moods followed the viewing of cult horror classics, namely the movies "Halloween" (1978, 1989) and "Scream" (1996).

After a particular series of clips, participants were asked to perform a difficult cognitive task requiring the active retention of information in short-term or "working" memory. Essentially, participants were shown a series of either words or unfamiliar faces on a computer screen, and had to indicate whether the current word (or face, in the face task) was the same as the one they had just seen three times back in the series.

The experiment studied the influence of relatively mild emotions on higher-level cognitive functions. In real life, such conditions might result from arguing with a spouse before leaving for work, or seeing a gory traffic accident on the way there. How might the lingering effects of these disturbing but not traumatic emotional experiences influence your job performance later in the day? Would the influence of various emotions be different if your job is highly verbal (defending a legal argument in court), as compared to highly non-verbal (monitoring plane on an air traffic control system)? The research suggests that the kind of job could make a big difference.

The research was supported by the National Science Foundation and the McDonnell Center for Higher Brain Function at Washington University in St. Louis.