Sad people are apparently better than happy people at face recognition, an upside to being down in the dumps that is yielding insights into how mood can affect the brain.
The findings, based on experiments involving college students, could help lead to better treatments for depression, psychologists say.
Past studies have found that unhappiness is often detrimental to a wide range of mental tasks, such as abstract thinking and remembering lists of words. A number of researchers had attributed this to brooding deeply and elaborately about one's surroundings, while others thought it might be due to being distracted by one's own concerns.
To learn more about how sadness might affect thinking, scientists tested undergraduate students in experiments involving face recognition. The researchers put volunteers into happy, sad or neutral moods by having them listen to suitable music — for instance, Mozart's "Requiem" for sadness, the theme from "The A-Team" for happiness, and the soundtrack for the movie "The Hunt for Red October" for a neutral mood. Participants were also asked to remember the happiest or saddest moments in their lives, or, for a neutral mood, their journey from home to the university.
In one experiment, 88 undergraduates were shown 32 faces with neutral expressions, then given a questionnaire as a brief distraction, then shown a sequence of 64 faces and asked to identify the ones they first saw. The volunteers primed to feel sad turned out to be the most accurate, and the happy ones the least accurate. [Read: Little-Known Disorder: People Can't Recognize Faces ]
"I was surprised," said researcher Peter Hills, a cognitive psychologist at Anglia Ruskin University in England. "Sad mood is usually associated with poorer performance in cognitive tasks."
In a similar experiment, 60 undergraduates viewed a series of faces with happy, sad or neutral expressions. Again, sad volunteers were the most accurate, regardless of the expressions on the faces they viewed. Intriguingly, volunteers in happy or neutral moods were more accurate at recognizing happy faces than sad ones.
"People prefer looking at happy faces — isn't a smiling face always more appealing than a sad one?" Hills said. "It may simply be that because we prefer looking at happy faces, we may pay more attention."
In the last experiment, 60 undergraduates were shown happy, sad or neutral faces and were asked to memorize them. Here the sad volunteers lost their advantage — all the volunteers performed about equally well at face recognition.
Elaborate thinking on the part of sad people could explain why they perform better at face recognition but worse at certain other tasks, the scientists said. That advantage goes away when happy people are asked to actively think about the world around them.
Past studies showed sad people are less accurate at recognizing words and objects. The fact that they seem better at recognizing faces may be due to their paying attention to more details than happy people do, helping them recall faces better, the scientists said.
"It is possible that sad people may be more susceptible to social cues," Hills added. "However, there is insufficient evidence at present to make this claim. I have other studies that show that sad people tend to look at different areas of the face than happy people, and this may cause them to be more accurate, but we don't really know yet."
"Although investigating sadness is useful in itself, the main focus is to try and understand how to prevent and treat depression," Hills told LiveScience. Perhaps understanding how sad people analyze faces could lead to a better understanding of how depression changes the way people view the world, pointing the way toward new avenues of therapy.
The scientists detailed their findings online Aug. 2 in the journal Consciousness and Cognition.