Because people recognize the same emotions across languages and cultures, psychologists have long suspected that a person's ability to perceive basic emotions is innate. However, a new study published in the June 18 early edition of the Proceedings of the National Academy of Sciences suggests that experience can alter the way people see emotions.
Led by University of Wisconsin-Madison psychologist Seth Pollak, the study examined how children categorize facial expressions as happy, sad, angry or fearful based on one particular emotional experience - physical abuse. Studying children who had been abused, Pollak says, offered an opportunity both to examine the effects of atypical experience on how children think about emotions and to possibly identify new interventions that could help abused children more effectively manage resulting behavioral problems.
For this study, Pollak invited both abused and non-abused children, 8 to 10 years old, to his Child Emotion Research Laboratory. There, they played computer "games" that presented digitally morphed photos of facial expressions that ranged from either happy to fearful, happy to sad, angry to fearful or angry to sad. While some of the faces expressed a single emotion, most were blends of two emotions.
In one of the games, the children saw a single face and had to choose which emotion it expressed the most. Because many images were a composite of emotions, this task allowed the researchers to determine how the children perceived different expressions.
Pollak, along with colleague Doris Kistler from the Waisman Center, a national center dedicated to advancing knowledge about human development, found that the two groups of children did categorize emotional expressions differently. While both abused and non-abused children generally responded the same way to expressions showing mostly happiness, sadness or fear, abused children identified more faces as being "angry," rather than fearful or sad. Even though an expression would show, for example, 60 percent fear and 40 percent anger, abused children would identify the latter emotion.
"There aren't differences in how the children recognize pictures of faces, but in how they categorize those faces. The abused children were more sensitive to anger," Pollak says. "Experience can shift where a person draws the boundary of a particular emotion, and this idea runs counter to claims that boundaries for emotions are innate."
Pollak says that the neural processes the brain uses to perceive and categorize emotion might be innate but that how people actually perceive and understand expressions of emotion can be shaped by experience.
Pollak's latest finding confirms the results of one of the psychologist's earlier studies, which found that children who were abused exhibited more brain electrical activity than non-abused children when shown angry faces, as opposed to other facial expressions.
"It may be the case that physically abused children develop a broader category of anger because it's adaptive for them to notice when adults are angry," he says.
But while this sensitivity could be protective in a threatening environment, it could be disadvantageous in others. An abused child might over-interpret a social cue, such as an accidental ball toss during recess, to be hostile. As a result, the child might try to protect himself by lashing out, calling names or exhibiting other inappropriate behaviors. By recognizing an abused child's sensitivity to cues of anger, Pollak says psychologists may be able to help these children respond more appropriately.
Through his research, Pollak hopes to not only understand better the effects of experience on how a person perceives emotion but to identify neurological aspects that are also affected by such experience.
"We are trying to add to the body of literature demonstrating the behavior problems observed in abused children," Pollak says. "We're looking at the problem of child abuse from the perspective of neuroscience and the developing brain." By doing so, he hopes to pinpoint underlying mechanisms that could lead to the development of tailored interventions to help abused children.
Pollak's work is supported by the National Institute of Mental Health and the UW-Madison Graduate School.
For more information on Pollak's work, visit: http://psych.
-- NOTE TO PHOTO EDITORS: High resolution photos of Seth Pollak, as well as images of the digitally morphed facial expressions used in the study, are available at http://www.