magazine issue 10 2009 / Issue 10

Do the Math: Cognitive Load Attenuates Negative Feelings

• written by Lotte van Dillen
• edited by Hans IJzerman

In other words, activities should distract people from their negative feelings to the degree that these activities incorporate mental resources: the more mental resources are needed to perform a task, the more emotional responses will be attenuated. In support of this, people report a greater reduction in negative mood when they perform a highly demanding task (i.e. solving complex, or unpredictable math problems) than when they perform a mildly demanding task (e.g. solving simple, or predictable math problems), whereas performing a mildly demanding task is still more distracting than performing no task at all (Erber & Tesser, 1992; (Van Dillen & Koole, 2007).

The Limited Resources of the Emotional Brain

If emotional information competes with non-emotional information for limited mental resources, this may be reflected in the dynamics of the brain systems involved. Several neuro-imaging studies have investigated how performing complex cognitive tasks can modulate emotional responses in the brain (Erk, Kleczar & Walter, 2007; Pessoa, Ungerleider, Gutierrez, McKenna, 2002; Van Dillen, Heslenfeld & Koole, 2009). For example, one study found that solving complex math equations attenuates responses to negative scenes in brain regions that are part of the emotion network, whereas performing the math task results in increased activity in regions that are part of the cognitive network in the brain (Van Dillen, Heslenfeld & Koole, 2009). Interestingly, there seems to be a linear relationship between these opposed neural patterns, such that the more cognitive brain regions are engaged during the task, the more activity in emotional brain regions are attenuated (Erk et al., 2007; Van Dillen, Heslenfeld & Koole, 2009).

Other researchers have reported similar effects of task complexity on brain responses to painful stimuli (Bantick et al., 2002;Frankenstein, Richter, McIntyre, & Remy, 2001; Tracey et al., 2002; Valet, et al., 2004). In one experiment, participants performed a counting task during which they received painful thermal stimulation. The counting task consisted of naming the number of words on screen regardless of the words’ meaning. Task complexity was manipulated by varying the possible interference of the words with the counting task (Bush et al., 1998), such that in the difficult task condition, participants had to count interfering number words, e.g. ‘eight’ or ‘five’, while in the easy task condition participants had to count neutral words, e.g. ‘cat’ or ‘frog’. Compared to the easy counting task, performing the difficult counting task significantly reduced people’s pain intensity scores to thermal stimuli, as well as activity in brain areas that process pain.

The Dynamic Interplay Between Task Load and Emotional Intensity

The above findings illustrate that cognitive tasks can reduce negative feelings because these require mental resources that would otherwise be used for the further processing of negative information. Whereas negative information generally draws a considerable amount of processing resources, strongly negative information has an even stronger impact on people’s mental capacity than mildly negative information (Mogg et al., 2000; Schimmack, 2005, Yuan et al., 2007). For example, people are more likely to ponder over a relationship break-up, than over a broken cup. Therefore, people’s negative emotional states should not only be affected by varying task demands, but also by the intensity of the negative information people encounter. In other words, a person’s momentary feeling state should be the result of the dynamic interplay between cognitive load on the one hand, and the intensity of the emotional trigger on the other hand.