BRAIN POWER: Discerning facial expressions is no easy task
BY DR. MAHA ALATTAR / FOR THE FREE LANCE-STAR
REMEMBER THE famous line in Christopher Marlowe’s poem about the face of Helen of Troy, whose abduction drove a fleet of ships into battle and ignited the Trojan Wars?
“Was this the face that launch’d a thousand ships; And burnt the topless towers of Ilium? Sweet Helen, make me immortal with a kiss.”
A single face might have launched a thousand ships, but a single glance has made millions fall in love. Facial expressions are so powerful that a single glance is enough to tell us whether a person is sad, happy or aggressive.
We draw quick conclusions about people’s personality, level of attractiveness and where their attention is directed—all based on their faces. Facial expressions help us communicate in ways that words cannot.
Our faces solidify the social fabric of society. Early humans used facial expressions before they had language. Infants and children use them before they learn to speak. Television and magazines bombard us with faces of celebrities. We are so wired to recognize faces that we see them in passing clouds.
Our facial expressions are constantly being molded by our skin and muscles, but they are controlled by the right and left hemispheres of our brains.
Each hemisphere of the brain has the ability to act independently, which makes our faces asymmetric. Each side expresses a slightly different emotion at one time.
The right side of the brain—which controls the left side of the face and body—is imaginative, artistic, adventurous and philosophical. It uses feelings rather than words.
The left brain—which controls the right side of the face and body—is detail-oriented, logical and good with facts, words and math.
The right side of our face reflects the more serious side of us, while the left side shows the world a more pleasant side of us.
Maybe that’s why a team of researchers showed that the left side of the face was rated as more aesthetically pleasant than the right side. This is believed to be due to the fact that we exhibit more intense emotions with our left side.
Facial expression is so important that we have a part of the brain dedicated to the interpretation of facial expressions and the perception of emotions.
It’s known as the fusiform gyrus, and it’s located at the bottom section of the temporal lobes on each side of the brain, sort of behind your ears.
A study in the May 2012 issue of Proceedings Biological Sciences concluded that the left fusiform gyrus helps us recognize “face-like” shapes in objects such as rocks or clouds. The right fusiform gyrus determines whether that feature is an actual human face or just a rock.
Prosopagnosia is the term used to describe the inability to recognize facial expressions; it is also known as face blindness. Damage to the fusiform gyrus from trauma or stroke can cause this impairment.
This part of the brain may help us understand why people with autism have impairments in social communication and facial recognition.
A study published in the September 2012 issue of Neuropsychologia showed that the ability to judge someone’s emotions by looking at his or her face was significantly impaired in adults with autism. Autism is associated with low activity in the fusiform gyrus and amygdala (an area that controls emotions).
ROLE OF GENDER, RACE
Another interesting thing about facial expressions is that men and women interpret them slightly differently. A study published in Neuropsychology in 2001 showed that men used the right side of the brain to process other people’s facial expression, while women used the left hemisphere.
Another study, published in the journal Brain and Cognition in 2002, showed that there is no difference in how men and women recognize facial expressions when they look at men’s faces. But women performed better than men in the recognition of female faces.
Studies also show that people are better at recognizing faces of members of their own race than faces of people of a different race.
This phenomenon is known as the “cross-race effect” or “interracial-face-recognition deficit.” In a study published in Perception in 2003, for example, Asian people were better able to recognize Asian faces, while Caucasian participants were better able to discern Caucasian faces.
A common result of this diminished familiarity with the other race’s facial expression is the tendency to see others and think “they all look alike.”
Another study, in the Journal of Applied Psychology in 1991, showed that white people performed significantly worse on trials involving African–American faces than on trials involving white faces. No such difference existed among African–American participants.
The science of how we recognize faces and interpret facial expressions is complex. The eyes, eyebrows, nose and mouth all play a role in what we see. And our brains are so complex they can make out expressions from undulations in the little hills and hollow caves of our faces.
If you’re wondering whether you have a preferred side of the face, visit echoism.org, a website where you can view photos of people’s faces and even upload photos of your own face. You might want to see how your left side compares to your right.
Dr. Maha Alattar is a board-certified neurologist and sleep specialist. She also is the director of the Mary Washington Healthcare stroke program. You can contact Dr. Alattar at Sleep Medicine Specialists in Fredericksburg at 540/741-7846.