Sept. 2, 2004 -- Being in a bad mood may make you a better eyewitness than someone who is happy, according to a new study that shows mood may have a powerful effect on memory.
Researchers found that being in a good mood made people more likely to include misleading details in eyewitness accounts. But being in a bad mood allowed them to give a more accurate account of events.
"It shows that our recollection of past events are more likely to be contaminated by irrelevant information when we are in a positive mood," says researcher Joseph Forgas, a professor at the University of New South Wales in Australia, in a news release. "A positive mood is likely to trigger less-careful thinking strategies."
Researchers say remembering personally witnessed events involves a series of complex processes that are open to a variety of influences and distortions, and this study shows that mood may play a major role in these processes and affect critical thinking skills.
"The finding makes sense in evolutionary terms," says Forgas. "Animals that are wary of their environment are more likely to perceive threats to their survival."
"This supports the idea that mood states are evolutionary signals about how to deal with threatening situations. That is, a negative mood state triggers more systematic, more attentive, more vigilant information processing," says Forgas. "By contrast, good moods signal a benign, nonthreatening environment where we don't need to be so vigilant."
Bad Moods May Improve Memory
In the study, researchers tested the ability of people to recall events under experimental conditions and in different mood states.
The results are scheduled to appear in an upcoming issue of the Journal of Experimental Social Psychology.
In one experiment, researchers had students witness a staged hostile exchange between a teacher and an intruder in a lecture hall. One week later, researchers used short, 10-minute videotapes to induce happy, neutral, or sad moods among the students. They were later asked to answer a questionnaire about the episode they witnessed that either did or did not contain misleading information. The researchers found they were more likely to recall the incident accurately a week later if they watched the sad videotapes than the happy one.
In another experiment, researchers put participants in a good or sad mood and then asked them to write down an argument in favor of a particular proposition. When the researchers analyzed the arguments for quality and persuasiveness, they found those written by students in a negative mood were far more effective than those penned by people in a happy mood.
Although the study showed that happy people made less-reliable witnesses, it also showed that being in a good mood increased people's confidence in the accuracy of their memory. Researchers say this finding shows that people are unaware of the effect their mood may have on how their mind may interpret or recall events.
Researchers say the study shows that being in a good mood increases the likelihood that false information will later be remembered as true and may have implications for forensic science and judicial proceedings that rely on eyewitness accounts.