Writing about stressful events has long been known to cause improvements in health and psychological well-being. Now, a new study provides clues to why that is.

The research, published in the September issue of APA's Journal of Experimental Psychology: General (JEP: General) (Vol. 130, No. 3), indicates that expressive writing reduces intrusive and avoidant thoughts about negative events and improves working memory. These improvements, researchers believe, may in turn free up our cognitive resources for other mental activities, including our ability to cope more effectively with stress.

In the past few years, research has hinted that a cognitive mechanism may help explain the link between expressive writing and health, notes University of Texas psychologist James W. Pennebaker, PhD, who has taken the lead, in the past decade, in research on expressive writing and health. He and his colleagues have found that the people who benefit most from expressive writing tend to use more causal analysis and express more emotion in their writing, leading some psychologists to speculate that expressive writing helps people simplify and organize fragmented memories.

The trouble, says Pennebaker, is that these ideas have been frustratingly vague. Now, he says, "Along comes this new study, which in my mind is almost revolutionary. It's a different level of analysis that none of us had thought about."

"If you're suffering from a traumatic or stressful event, your ability to pay attention and focus on life's stressors isn't what it should be," proposes the study's lead author, North Carolina State University psychologist Kitty Klein, PhD.

As a consequence, she suggests, "It's going to take you a lot longer to come up with effective coping strategies. That may be a vehicle for getting you into poorer and poorer health."

The new results hint at a way to short-circuit that destructive process, says co-author Adriel Boals, now a postdoctoral fellow at Duke University. "They suggest that at least for fairly minor life problems, something as simple as writing about the problem for 20 minutes can yield important effects not only in terms of physical health and mental health, but also in terms of cognitive abilities," he says.

Writing about college stress

In an initial experiment, Klein and Boals examined how writing about a stressful event affected working memory for 71 undergraduates. The participants completed three 20-minute writing sessions during a two-week period. Half, assigned to an "expressive writing" condition, were instructed to write about their deepest thoughts and feelings about coming to college and to "tie it all together" at the end of their essays. Participants in a control condition instead wrote about what they had done that day and how they might have done a better job.

Using a standard test of verbal working memory, Klein and Boals measured participants' working memory capacity three times: once before the first writing session, and again one week and seven weeks after the last writing exercise.

The researchers also examined the content of participants' essays, probing for "cause and insight" words--such as "hence," "because" and "therefore"--that might signal efforts to create a more coherent narrative out of fragmented stressful memories. Finally, the team measured the link between working memory improvement and academic performance, using students' grade-point averages (GPAs) for the semester during which the experiment took place and the following semester.

The results revealed that participants in the expressive-writing condition showed modest improvements in working memory between the second and third memory tests. In contrast, control participants showed no such improvement.

In addition, participants in the expressive-writing condition used more cause and insight words than did those in the control group, strengthening the notion that expressive writing boosts the narrative coherence of stressful memories. Gains in working memory were also associated both with greater use of cause and insight words and with higher GPAs both immediately after the experiment and in the subsequent semester.

Intrusive thoughts

Although that first experiment provided tantalizing support for the idea that expressive writing may improve working memory, it did not firmly establish whether expressive writing freed memory resources by purging people's intrusive and avoidant thoughts about stressful experiences.

The experiment also revealed only modest effects of expressive writing on working memory. Such effects may have been dampened, the authors hypothesized, by the writing task itself: Because going to college is not a uniformly stressful experience, expressing one's feelings about it may have less benefit for some people than for others. And instructing participants in the control group to think about how they could have better spent their time may have inadvertently encouraged them to form more coherent cognitive representations of their day, enhancing working memory.

To address these issues, Klein and Boals tweaked the writing task in a second experiment, asking some participants to write about an extremely negative experience and others to write about an extremely positive one. Participants in a control group again wrote about their day's schedule, but this time, they were not prompted to evaluate the day.

To test the link between expressive writing, intrusive thoughts and working memory, the researchers also asked participants to indicate, at the beginning and end of the experiment, how frequently unwanted memories of their most negative and positive experiences intruded into their thoughts and how often they avoided thinking about the experiences.

The results revealed that participants who wrote about a negative event had fewer intrusive and avoidant thoughts and showed sizable improvements in working memory, compared with those who wrote about a positive event and those in the control group. Further, mediational analyses suggested that expressive writing works to boost working memory only when a person has fewer intrusive and avoidant thoughts. Finally, as in the first experiment, working memory improvements were again associated with higher GPAs, as were reductions in intrusive thoughts.

Unanswered questions

The findings are exciting for a number of reasons, say psychologists. In a practical sense, the results suggest that the simple act of writing about stressful events can have a positive impact on academic performance--although for how long remains unknown. And as a "first stab" at explaining what's behind the well-established connection between writing and health, says Pennebaker, "This paper is just remarkable. My only regret is that I didn't think of it first."

What's equally striking, says cognitive psychologist Akira Miyake, PhD, of the University of Colorado, is the finding that working memory is malleable and can be affected by a psychosocial task such as expressive writing. That, he argues, has repercussions not only for physical health, but for a range of domains in which working memory might be impaired. For instance, college students who have math anxiety and fear statistics often experience working memory deficits while working on math problems because of intrusive thoughts and worry about math. Such students, Miyake suggests, might benefit from writing about their anxiety.

But even as Klein and Boals's findings provide exciting clues to why expressive writing exerts such a powerful effect on people's well-being, the study leaves unanswered questions--among them, why does expressive writing squash intrusive thoughts and improve working memory?

Pennebaker and others have theorized that forming a more coherent narrative surrounding fragmented memories--as is evidenced by increases in cause and insight words--helps free up working memory. Yet Klein and Boals found working memory effects only for participants who wrote about negative experiences, despite the fact that the two groups showed the same improvements in their use of cause and insight words--an effect that is unexplained by that theoretical rationale.

One possible explanation, suggests Klein, is that positive events simply have less cognitive impact than negative events. That may be particularly true for college students, who, Klein believes, tend to take positive events for granted.

Miyake suggests an alternative explanation, which dovetails with the results of another article in the same issue of JEP: General, by Washington University psychologist Jeremy R. Gray, PhD. In his research, Gray found that verbal working memory is impaired by negative emotion, but not by positive emotion. The opposite, he showed, is true for visuospatial working memory.

To the extent that repeated writing about negative events decreases their emotional impact, Miyake speculates, it may lead to improvements in verbal working memory. If such a mechanism is indeed responsible for Klein and Boals's results, says Miyake, it may be that tests of visuospatial working memory would reveal a similar effect of writing about positive events.

This article is part of the Monitor's "Science Watch" series, which reports news from APA's journals.