The University Record, July 19, 1993

Psychological ‘volume control’ dampens or elevates effect of sensory stimuli

By Deborah Gilbert
News and Information Services

Roughly one out of four of us may choose to feel bad rather than feel nothing at all, according to preliminary research at the University.

Such a choice may depend in part on an inherent regulator in the brain called a “stimulus intensity modulation mechanism,” according to Randy J. Larsen, associate professor of psychology.

“The mechanism functions as a psychological ‘volume control’—a regulator that dampens or elevates the effect of sensory stimuli,” Larsen says.

In most of us, the regulator is set at an optimum mid- range, which keeps us from being either overstimulated or understimulated.

“But in the 1970s, researchers discovered that some individuals have regulators set at one extreme. Among people we call ‘reducers,’ the regulator seems to buffer the brain, reducing the effect of stimuli. Since they often feel stimulation-deprived, many reducers compensate by throwing themselves into high-risk activities or novel situations like mountain climbing, simply in order to feel alive,” Larsen explains.

At the other extreme are the “augmenters,” people whose regulators elevate stimuli, so they avoid risky or novel situations that may overstimulate them.

Now, according to Larsen’s experiments, the same general tendency to reduce or augment seems to hold true for emotions.

In one of his studies, 47 students filled out a reducer/augmenter tendency questionnaire, checking off whether they liked or disliked contact sports, bright lights and loud noises, could tolerate much pain, and so on.

They then sat in separate booths for 35 minutes while they tackled a set of 1,584 simple, two-digit addition and subtraction problems. They were not allowed to talk, get out of their seats, make distracting noises or wear watches.

“Every five minutes, we asked them to circle the problems they were on so we could assess changes in performance speed,” Larsen says.

After 35 minutes, the students rated how interesting and pleasant they had found the mathematics task, and estimated how long they had worked on the problems.

“Then we asked them to select one of two other experiments to be in. The experiments were just hypothetical, but the students thought they were real,” he says.

The students could choose to answer a series of questionnaires about mundane, daily behaviors such as what they ate for breakfast or how often they brushed their teeth, or they could choose to view a film showing very negative, very emotional scenes that would upset them.

“We told them that after the distressing film, they would answer a very brief questionnaire and have a short rest to calm down,” Larsen says.

Eleven of the 47 students chose to see the upsetting film rather than endure more tedium. “All 11 were reducers, according to their reducer/augmenter tests. They preferred to be aroused, even if the arousal was unpleasant. Anything was better than being understimulated.

“The reducers also remarked that they found the math problems excruciatingly dull, and that group had performed more and more slowly as time passed,” Larsen says.

In the second experiment, another 43 students took the reducer/augmenter tendency test and kept daily mood diaries, noting mood swings and mood intensities. They also reported how many times a day they sought out novel or stimulating activities.

“Once again, we found that the reducers were more likely to opt for high sensation, high arousal events when they could. They preferred to go to movies rather than read books, play loud music, and join in group activities. They also reported having more intense emotions and wider mood swings than the augmenters,” Larsen says.