“Face blindness” is a common heritable disorder

There’s some new research out that is showing that so called “face blindness” (prosopagnosia or PA for short) is a common heritable disorder.

Face blindness is a common hereditary disorder

In the first study to examine whether the inability to recognize faces can be inherited, researchers found that it is in fact a common disorder that runs in families and is one of the most frequent disorders apparently controlled by a defect in a single gene. The study was published online June 30, 2006 in American Journal of Medical Genetics Part A, and is available via Wiley InterScience at http://www.interscience.wiley.com/ajmg.

Prosopagnosia (PA) or face blindness is characterized by the inability to differentiate faces, except for the most familiar ones such as members of one’s family. It can be caused by brain injury, but cases where the disorder appears to run in families have also been reported. In the first systematic study of hereditary prosopagnosia (HPA), researchers led by Ingo Kennerknecht, M.D. of the Institute of Human Genetics at the University of Muenster in Germany, recruited 689 subjects from local secondary schools and a medical school and administered a questionnaire to identify those with suspected HPA. They found 17 cases of the disorder, and of the 14 subjects who consented to further interfamilial testing, all of them had at least one first degree relative who also had it.

“Nearly all affected persons report a problem in deciding immediately whether a face is known,” the authors state. Subjects report uncertainty in social situations and the inability to visualize the faces of close relatives or recall mental images of trees, leaves, or birds. They generally have difficulty following TV programs or movies because they cannot tell similar actors apart. All of the PA subjects revealed that they used up to three different strategies for overcoming the disorder. In the compensation strategy, subjects attempt to recognize people by other characteristics such as voice, gait, clothing or hair color. In the explanation strategy, subjects have a ready set of excuses as to why they can’t recognize someone, such as being deep in thought or needing new glasses. In the avoidance strategy, subjects try to avoid situations where they might be unable to recognize faces, such as large functions or crowded places.

Because of the compensation strategies that those with PA learn to utilize at an early age, many of them do not realize that it is an actual disorder or even realize that other members of their family have it. “This could explain why this kind of cognitive impairment is largely unknown to lay persons or even to physicians other than neurologists and psychiatrists,” the authors state, adding that there are no established diagnostic tools for PA.

While face recognition is strongly affected in HPA, the processing of other facial information, such as gender, age, and emotional expression is generally intact. This suggests that facial information and these other characteristics are processed independently of one another. Furthermore, HPA is one of the few cognitive functions or dysfunctions that has only one symptom and is inherited, the authors note.

“Neurophysiological studies of people with this highly selective dysfunction might fundamentally improve our understanding of face recognition,” the authors conclude. “As soon as gene mapping/mutation mapping will be successful, the genotype/phenotype correlations should widen our knowledge of the development of higher cerebral functions.”

In highschool I had trouble confusing people I didn’t know well with others who were of similar height and hair color. I wonder if I qualify as a possible PA candidate? I don’t seem to have that problem as much anymore. I also seem to recall reading a while back that this was associated with dyslexia as well.

Are Social Outsiders Less Human?

A recent study came out showing that based on fMRI scans social outsiders are, well, essentially treated as something slightly less than human when it comes to the way the brain processes them.
Read on:

Detecting prejudice in the brain

Three Florida teenagers recently pleaded not guilty to the brutal beatings and in one case, death, of homeless men. One of the beatings was caught on surveillance video and in a most chilling way illustrates how people can degrade socially outcast individuals, enough to engage in mockery, physical abuse, and even murder. According to new research, the brain processes social outsiders as less than human; brain imaging provides accurate depictions of this prejudice at an unconscious level.

A new study by Princeton University psychology researchers Lasana Harris and Susan Fiske shows that when viewing photographs of social out-groups, people respond to them with disgust, not a feeling of fellow humanity. The findings are reported in the article “Dehumanizing the Lowest of the Low: Neuro-imaging responses to Extreme Outgroups” in a forthcoming issue of Psychological Science, a journal of the Association for Psychological Science (previously the American Psychological Society).

Twenty four Princeton University undergraduates viewed a large number of color photographs of different social groups (including Olympic athletes, business professionals, elderly people, and drug addicts), and images of objects (including the Space Shuttle, a sports car, a cemetery, and an overflowing toilet) that elicited the emotions of pride, envy, pity, or disgust. The four emotions were derived from the Stereotype Content Model (SCM), which predicts differentiated prejudices based on warmth and competence. Warmth was determined by friendliness, competence by capability. The two emotional extremes were pride and disgust; pride elicited high warmth and high perception of competence, and disgust elicited low warmth and low perception of competence. Envy and pity were considered moderate prejudices; envy elicited low warmth and high perception of competence, and pity elicited high warmth and low perception of competence.

Medial prefrontal cortex (MPFC) brain imaging determined if the students accurately chose the correct emotion illustrated by the picture (according to pretest results in which a different group of students determined the emotion that best fit each photograph). The MPFC is only activated when a person thinks about him- or her-self or another human. When viewing a picture representing disgust, however, no significant MPFC brain activity was recorded, showing that students did not perceive members of social out-groups as human. The area was only activated when viewing photographs that elicited pride, envy, and pity. (However, other brain regions — the amygdala and insula — were activated when viewing photographs of “disgusting” people and nonhuman objects.)

Emotions themselves were not responsible for generating this brain activity. Rather, it was the actual image viewed that produced a response. The MPFC only showed significant activity when a person saw or thought about a human being. The authors conclude that this lack of MPFC brain activity while viewing photographs of people proves that “members of some social groups seem to be dehumanized.”

Social out-groups are perceived as unable to experience complex human emotions, share in-group beliefs, or act according to societal norms, moral rules, and values. The authors describe this as “extreme discrimination revealing the worst kind of prejudice: excluding out-groups from full humanity.” Their study provides evidence that while individuals may consciously see members of social out-groups as people, the brain processes social out-groups as something less than human, whether we are aware of it or not. According to the authors, brain imaging provides a more accurate depiction of this prejudice than the verbal reporting usually used in research studies.

As politically incorrect as it is, it is obvious that nature itself determines that humans will have prejudices against other humans.