Our emotions play an important role in how we cognitively process information. Anger, in particular, can short-circuit our ability to think through things, and increases our reliance on "heuristics" or mental shortcuts.
What type of mental shortcuts am I referring to? A study by Bodenhausen, Sheppard, and Kramer in 1994 illustrates this point. The researchers had participants vividly recall either an experience that either made them really angry or really sad, and then exposed them to an essay arguing in favor of raising the legal driving age from 16 to 18. The essay that participants read were attributed either to "a group of transportation policy experts at Princeton University" or to "a group of students at Sinclair Community College in New Jersey." In reality, the essays that the participants read were exactly the same, so only the supposed author (the "source") of the message differed. Afterward, all participants were asked how persuaded they had been by the arguments. Now, whereas the sad participants did not differ in how persuaded they were depending on the message source, the angry participants were significantly more persuaded if the (same) message was attributed to the Princeton policy experts.
Why the different reactions among angry vs. sad participants? The persuasive messages that the researchers devised could be processed in one of two ways. If participants engaged in systematic information processing, they should think carefully and analytically about the arguments being presented, without being swayed by the message source. If participants engaged in heuristic information processing, by contrast, they should rely more on surface-level features of the message-- such as the credibility of the source. The results clearly showed that the angry participants were relying more on the heuristic features of the message, since they found the exact same message more persuasive based on who the message was attributed to.
Whereas sadness is an emotion that tells us there is a need for caution, and thus increases systematic information processing, anger is an emotion that tells us there is a need for quick action, and thus increases heuristic information processing. Thus, when we are angry, we tend to use mental shortcuts to decide whether an argument is right. Source credibility is one such shortcut. Another is the "length is strength" heuristic, in which we decide an argument is stronger or more persuasive only because it is longer.
Yet another type of mental shortcut that people use when they are angry is stereotypes. In the same study by Bodenhausen and colleagues, angry participants were more likely than sad participants to find the same set of evidence as indicative of guilt when a criminal defendant was named as "Juan Garcia" as opposed to "John Garner." Again, the angry participants went with the heuristic-- in this case, the stereotype of Latinos as criminal - rather than focusing on the evidence per se.
Copyright 2011 by Rodolfo Mendoza-Denton; all rights reserved.