Eyes on the Brain

A neurobiologist explores the amazing capacity of the brain to rewire itself at any age

Is Face-Blindness Curable?

Retraining old brains: curing face-blindness and other perceptual deficits.

I have a friend who never forgets a face. She can bump into people she hasn't seen in decades and recognize them immediately. I am amazed by her ability, have nicknamed her "the woman with two brains," and wish I had her skill. I can spend an entire evening in face-to-face conversation with someone new and not recognize them the next day. I need to see someone many times over before I'll recognize their face.

The ability to recognize another's face is thought to be an innate human skill. Babies, just nine minutes old, show a preference for looking at human faces. Specific areas of the brain, including the fusiform face area and occipital face area, are largely devoted to facial recognition. Yet, the ability to identify another's face varies from person to person, and a small but significant minority of the population struggle with facial recognition. They may suffer from varying degrees of "face-blindness" or, more technically, prosopagnosia. You can explore your own facial recognition skills by going to www.faceblind.org.

Can face-blindness be cured or are you born with a certain, unchanging aptitude for facial recognition? One of the primary adaptations to any deficit is avoidance. Since I am poor at recognizing faces, I avoid situations, like attending large meetings or parties, where facial recognition skills are important. I find watching movies to be a frustrating experience because I can't recognize the same characters from one scene to the next. Not surprisingly, I don't often go to movies and, thus, lose an opportunity for practicing and perhaps improving my facial recognition skills. My friend, on the other hand, who is a whiz at recognizing faces, watches lots of movies and continues to hone her genius for facial recognition.

Thus, our own deficits may lead, through habits of avoidance, to greater deficits and our strengths may lead to greater strengths. Yet, all is not hopeless. I recently read a paper in the Journal of Cognitive Neuroscience on curing face-blindness. The investigators studied a 48-year-old woman, MZ, who had always had trouble recognizing faces. In one test, for example, she could identify only 5 out of 20 famous faces while most people could identify 16. She had no difficulties, however, in identifying animals or nonliving objects, and she had no other visual or cognitive problems.

The investigators hypothesized that MZ did not have trouble with picking out specific features in a face, such as big ears or a large nose. Her deficit lay in processing the whole face, in seeing the spatial relationships between different features. Thus, MZ's training required her to view computer-simulated faces and categorize the faces as belonging to one of two groups depending upon the distance of the eyebrows from the eyes and the distance of the mouth from the nose. After only one day, MZ showed considerable improvement in both speed and accuracy when completing this task, and after 1 week of daily training consisting of a total of 4,000 trials, MZ's performance approached but did not quite reach normal levels. Most importantly, she reported that her ability to recognize faces in daily life had improved dramatically.

However, training was then stopped, and after a month, MZ found that her newfound ability to recognize faces had disappeared. She then underwent a second interval of training, both in the laboratory and with home exercises, and quickly regained and then surpassed the skills she had developed after the first training bout. Indeed, her performance reached normal levels.

MZ's story reminds me very much of my own experience with gaining stereovision (3D vision) through optometric vision therapy. Both MZ and I were 48 years old when we began our therapy, that is, we were both too old, it was once thought, to gain new perceptual skills. However, an older brain still retains the ability to rewire and reorganize. It is however more set in its ways. Changing an adult brain requires extra effort as both MZ and I discovered:

For MZ to learn to recognize faces, she had to change old habits. She had to change the way she evaluated faces, and this change required CONSCIOUS ATTENTION. For me, to develop stereovision, I had to learn how I habitually directed my two eyes when looking at a visual target, and then consciously change the way that I aimed them. The older you are, the harder it may be to change long-standing habits, but it is not impossible.

After each trial, MZ received FEEDBACK telling her whether or not she had separated the faces into the proper categories. Similarly, I practiced vision therapy procedures that continually provided me with feedback as to where I was pointing my two eyes. Feedback is crucial to developing new ways of seeing.

MZ PRACTICED her facial recognition tasks over and over again and I practice vision therapy procedures almost every day. Like an athlete or musician honing their skills, there's no substitute for practice.

In addition to her standard facial recognition tasks, MZ also practiced a task involving the recognition of upside-down faces. She got better at this task, but this skill did not translate into recognizing faces in their normal upright orientation. For MZ to get better at recognizing faces as they are normally seen, she had to work SPECIFICALLY at tasks involving upright faces. Similarly, for me to gain stereovision, I had to work specifically at tasks that required me to fuse or merge input from the two eyes. If you have a deficit in a certain skill, you need to concentrate on that particular skill to get better.

MZ's facial recognition abilities decreased when she stopped practicing, and my stereovision declined when I stopped my vision therapy procedures for six months. These problems were quickly reversed when we renewed our training. If I had learned how to see in stereo as a very young child, I might not need to CONTINUE TO PRACTICE vision therapy procedures today. An older person like me, however, who has habitually used a different style of seeing for many years, must continually remind her brain to see in a new way.

Old habits, as they say, die hard but they can be broken. As these stories of face-blindness and stereoblindness indicate, with the right kind of therapy, motivation, and practice, an older brain can rewire, reorganize, and recover.

 

Susan R. Barry, Ph.D., is a professor of neurobiology in the Department of Biological Sciences at Mount Holyoke College and the author of Fixing My Gaze (June, 2009).

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