WSJ 31st August 2011
A college student deep into studying for a big exam might do well to give his brain a break.
Just what he does during that break will determine how helpful that pause will be, a growing body of research shows. A stroll in the park could do wonders, for instance, while downing coffee could leave him just as stressed and depleted as before the break. And, sometimes, forcing oneself to simply power through mental fatigue can be more effective than pausing.
Like a muscle, our brains appear to get fatigued after working for sustained periods of time, particularly if we have to concentrate intensely or deal with a repetitive task, says Michael Posner, an emeritus professor at the University of Oregon who studies attention.
Researchers are zeroing in on some of the circumstances that bring about optimal mental refreshment.
Taking in the sights and sounds of nature appears to be especially beneficial for our minds, researchers say.
Marc Berman, a post-doctoral researcher at Rotman Research Institute in Toronto, and his colleagues are studying whether interacting with nature can be therapeutic for people with disorders including depression and anxiety.
This work follows research by Dr. Berman and partners at the University of Michigan showing that performance on memory and attention tests improved by 20% after study subjects paused for a walk through an arboretum. When these people were sent on a break to stroll down a busy street in town, no cognitive boost was detected.
In a follow-up study, the researchers had participants take a break for 10 minutes in a quiet room to look at pictures of a nature scene or city street. Again, they found that cognitive performance improved after the nature break, even though it was only on paper. Although the boost wasn't as great as when participants actually took the walk among the trees, it was more effective than the city walk, says Dr. Berman.
The result wasn't due to participants in the studies being in a better mood after the nature scenes, according to the research, which was published in the journal Psychological Science in 2008. In fact, some people were assigned to walk in the arboretum during a Michigan winter.
"You don't necessarily have to enjoy the walk to get the benefit," says Dr. Berman. "What you like is not necessarily going to be good for you."
Rather, the researchers say, nature images engage our so-called involuntary attention, which comes into play when our minds are inadvertently drawn to something interesting that doesn't require intense focus, like a pleasing picture or landscape feature. We can still talk and think while noticing the element.
By contrast, individuals rely on directed attention when they need to focus on work or potential threats, such as car traffic when crossing the street. It is this type of attention that can flag when used for long periods.
Engaging involuntary attention may allow directed attention time to recover, the research suggests, whereas the focus required on a busy street doesn't give the brain much chance to rest its directed-attention resources.
People who don't live in or near a nature-filled environment may not be out of luck, says Dr. Berman. A quieter city street with interesting natural elements to look at, such as containers of plants, could do the trick, too, he says. Dr. Berman and his colleagues are now trying to figure out exactly what elements of natural environments trigger the cognitive benefits.
The timing of a break also matters. People don't get the cognitive benefit when feeling rushed or under harsh time pressure. At those times, it may be best to just keep working, psychologists say.
The benefits of another popular way people try to refresh themselves—a coffee break—aren't clear cut, either, researchers say. While caffeine indeed revs up the body, including the brain, that doesn't necessarily translate to better performance, researchers at the University of Bristol found.
In talking with attendees at a stress-management conference who had access to unlimited coffee during breaks, some reported feeling more stressed after drinking additional caffeine. The researchers followed up with a study of 64 coffee drinkers and found that men who drank more than their usual amount of coffee performed worse when working on a group assignment.
The same didn't hold true for women, likely because they tend to perform better in groups, says Lindsay St. Claire, a lecturer at the University of Bristol in the U.K. who was part of the team that conducted the study, published last year in the Journal of Applied Social Psychology.
"The arousal from caffeine can prolong the arousal you would have from stressful situation," which can be detrimental, says Dr. St. Claire. So, she says, people should consider how keyed up they already are feeling before pausing for an additional cup of coffee.
While we seem to need a break from focused work at some point, people can push themselves beyond what they might think they are capable of, according to a study published in Psychological Science in September.
The notion of willpower as a resource that people can strengthen with exercise has gotten recent attention with the publication of "Willpower: Rediscovering the Greatest Human Strength," by Roy F. Baumeister and John Tierney.
In the September study, Stanford University researchers showed that people who believe they have an unlimited amount of willpower were able to work longer—without performing worse—than people who believe that they have only limited willpower.
Both groups reported feeling tired. But researchers subtly suggested in questionnaires to some participants that they had stamina that could be replenished, and this group appeared to overcome the fatigue. A possible reason is that forcing themselves to not think about being tired freed up some additional cognitive resources to work longer on the task at hand, says Veronika Job, a study author now at the University of Zurich.
The message, says Dr. Job, is that you can power through a period of high concentration, such as a final exam, if you believe you have unlimited willpower. The researchers are currently studying whether people can make lasting changes to their lives, based on their belief in their willpower. Such research could eventually help people, for example, stick to healthy diets or better regulate their emotions.
"When you have a limited mindset, maybe you'll be able to push yourself through a task, but in the evening you'll think, 'Now I'm done,' " says Dr. Job. Having a sense of increased willpower might make it easier for a person to say no to indulging in candy bars, even after a long day, she says.