(Oct. 9, 2001)
A study by an East Carolina University psychologist offers new evidence that the brains of boys and girls are organized differently, and the research also suggests that men and women who suffer brain injuries would benefit from separate treatment regimens.
Conducted at the State University of New York at Buffalo School of Medicine and Biomedical Science, the study was led by Dr. D. Erik Everhart, a professor at ECU. Everhart held a neuroscience fellowship at Buffalo before joining ECU last year.
The study concluded that boys and girls between the ages of 8 and 11 use different parts of the brains to recognize faces and identify facial expressions. The boys used more of their right brain to recognize faces while the girls used more of their left.
An article about the research appeared in the July issue of "Neuropsychology," published by the American Psychological Association.
Everhart said the study shows that there are sex-related differences in brain organization and in how people perceive emotion, and these differences are present in children even before the onset of puberty.
"My research has been on identifying the brain regions involved in perception of different emotions such as happiness, sadness, anger, fear and the expression of these emotions through facial expressions and through voice and speech," said Everhart.
He said science has known for a long time that the left side or hemisphere of the brain is somewhat specialized for language and any time there is an injury to the left side such as a stroke, language is affected. The way the brain works on the right side is more of a mystery.
For example, damage to the right side can produce no identifiable deficits. A stroke victim might get an "OK" from the doctor and released from the hospital, but the victim's family will notice a difference in the person who might look depressed but would deny it. In many cases the patient is unaware that there is a problem.
"In the past 25 to 30 years we have slowly identified that the right brain is specialized to expression and perception of emotion including understanding the facial expression like being happy and sad or angry," said Everhart. "You can have strokes in the right hemisphere and lose the ability to perceive an angry face, an angry tone of voice and, depending on where the damage is, you can lose the ability to produce those kinds of things," he said.
"I've focused on people without brain damage or strokes to see how the normal population does these things, but we are finding that there are sex-related differences. This fits with what we suspect -- that men have areas that are more highly specialized than women, but women are more global and are able to adapt," he said.
Everhart's study tested 17 boys and 18 girls. The youths performed two different types of tasks. For the face-recognition-memory task, they viewed a series of three-slide sets. In each set, the first slide had a face with an "x" in the middle to help focus their gaze. The second slide gave them a "target" face to study. The third "recognition" slide offered three faces, from which they had to choose the target face regardless of expression.
The children wore a type of multi-wired cap to produce an electroencephalo-graphic (EEG) that shows the brain waves changes in the left and right hemispheres as the recognition tasks are performed.
In the second task, to identify the expression of emotion, the children viewed slides of people's faces and matched them up with other slides that depict different types of emotion. The researchers tallied the accuracy and response times, but did not use an EEG measurement.