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How Common Is Face Blindness?

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How Common Is Face Blindness?

Study suggests condition affects more people than previously thought​

By DENNIS NEALON February 24, 2023 Research
hms.harvard.edu

In the new study, led by Joseph DeGutis, HMS associate professor of psychiatry at VA Boston, the researchers found that face blindness lies on a spectrum — one that can range in severity and presentation — rather than representing a discrete group. The authors also provide diagnostic suggestions for identifying mild and major forms of prosopagnosia based on guidelines for major and mild neurocognitive disorders in the DSM5, the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders.

The study results are based on a web-based questionnaire and tests administered to 3,341 individuals. First, the researchers asked participants whether they experience difficulties recognizing faces in their everyday lives. Then they administered two objective tests to determine whether they had difficulties learning new faces or recognizing highly familiar, famous faces.

The results showed that 31 individuals out of the 3,341 had major prosopagnosia, while 72 of the 3,341 had a milder form. The researchers also observed that there were no neatly divided discrete groups of people with poor or good ability to recognize faces. Rather, the ability to recognize faces appeared to lie on a continuum, they said.

Finally, the researchers compared face-matching scores among people with prosopagnosia diagnosed using different criteria and found that using stricter diagnostic cutoffs did not correspond with lower face-matching scores.

Harvard Medicine News spoke with DeGutis, the study’s senior author, about the implications of the findings.

Harvard Medicine News: Let’s start with the basics. What causes face blindness?

DeGutis:
Prosopagnosia, or face blindness, can be caused by a brain injury to occipital or temporal regions, referred to as acquired prosopagnosia, which affects one in 30,000 people in the United States. Prosopagnosia can also be a lifelong condition caused by genetic or developmental abnormalities, referred to as developmental prosopagnosia, affecting one in 33 people.

HMNews: This is a fascinating condition, but some might say that it’s not a serious health disorder so why is it important to study and understand it?

DeGutis:
First, face blindness can be a socially debilitating disorder that can limit employment opportunities. For example, networking is extremely difficult for people with prosopagnosia and can cause social distress and embarrassment. Recognizing someone is a social signal, indicating that “you are important to me.”

Prosopagnosia can also affect individuals on the autism spectrum and can be a consequence of age-related cognitive decline as well. In a world where social isolation is on the rise, especially in teens and young adults, fostering and maintaining social bonds and good face-to-face interactions are more important than ever.

HMNews: What sparked your interest in this field? What is it about how the brain sees and remembers faces intrigues you the most and why?

DeGutis:
Face blindness is fascinating on several levels. Humans are remarkably good at recognizing familiar faces and this is done with very little effort. We know that this face ‘super-power’ relies on several specific perceptual processes: holistic face processing-seeing the face as an integrated whole, for instance; memory processes, readily associating faces with person-related knowledge; and specialized brain mechanisms and regions, too, such as the fusiform face area.

Our knowledge about face recognition in unimpaired individuals provides a very solid framework to understand the ways these processes can break down in prosopagnosia. The processes also provide clues on how to improve face recognition in people with face blindness, which is one of the major goals of our lab. Finally, studying prosopagnosia is fascinating from a phenomenological perspective—what do people with face blindness actually “see” when looking at a face? What comes to mind when they think about a familiar friend’s face?

HMNews: You say that your findings call for an expansion of the diagnostic criteria. Why is that important?

DeGutis:
This is important on several levels. First, the majority of researchers have used overly strict diagnostic criteria and many individuals with significant face- recognition problems in daily life have been wrongly told they do not have prosopagnosia. Expanding the diagnosis is important because knowing that you have real objective evidence of prosopagnosia, even a mild form, can help you take steps to reduce its negative impacts on daily life, such as telling consequential coworkers, or seeking treatment.

Recent evidence suggests that people with milder forms of face blindness may benefit more from certain treatments than people with more severe forms of the condition. These treatments might include cognitive training to enhance perceptual abilities or training aimed directly at improving face associations.

Finally, factors such as age-related cognitive decline and social anxiety can further worsen face recognition abilities. Knowing if you have mild prosopagnosia could help you keep an eye out for further situational or age-related declines in face-recognition ability.

HMNews: What do you want clinicians and individuals with the condition to take away from these results?

DeGutis:
The take-home message is that prosopagnosia lies on a continuum and stricter vs. looser diagnostic criteria employed in prosopagnosia studies in the past 13 years have identified mechanistically very similar populations, providing justification for expanding the criteria to include those with milder forms of it.

Another take-home message is the importance of using a combination of self-reported daily-life difficulties and validated objective measures when diagnosing prosopagnosia.

There are pros and cons to relying just on self-reports because it can be challenging to judge your own abilities or relying solely on objective lab measures that may not reflect everyday life.

This interview was edited for length and clarity.

https://hms.harvard.edu/news/how-common-face-blindness

https://www.medicaldaily.com/harvar...indness-more-common-previously-thought-468297
 

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What Is Face Blindness? - Science Friday
www.sciencefriday.com

Male and female faces, from Shutterstock
Male and female faces, from Shutterstock

When Lisa Brown was about five, she got into a tiff with two friends who were brothers. It happened at their house after lunch, when she started interchanging their names. “They got very upset with me,” she remembers. But she wasn’t trying to provoke them.

Brown has prosopagnosia, commonly called face blindness, which means she has trouble recognizing familiar faces and learning to recognize new ones. To keep track of the brothers, she would usually memorize what color shirt each was wearing. But earlier that day, the boys had gotten dirty and changed, throwing her off.

Brown, who’s now 37, didn’t know that her difficulty with faces had a name until a few years ago, when her spouse heard a radio show discussing the topic of prosopagnosia and realized that she seemed to fit the description. Brown later got in touch with researchers studying the subject, who confirmed that she met certain criteria for a diagnosis.

“It was very validating to know,” she says. “I have always believed my whole life that if I could just pay more attention, I would be better at [recognizing faces], and people wouldn’t get upset with me for it.”

Researchers recognize two types of prosopagnosia—a rare, acquired type, and a more common form called developmental prosopagnosia. People with the acquired type have lost the ability to recognize faces due to some sort of brain injury, such as a stroke. For those with the other type, certain brain mechanisms failed to develop properly, perhaps for genetic reasons (it does seem to run in families).

While cases of acquired prosopagnosia have been known since the mid-19th century, the first report of developmental prosopagnosia didn’t appear until 1976. “It took us a lot longer to recognize it,” says Brad Duchaine, an associate professor in the Department of Psychological and Brain Sciences at Dartmouth College who has been studying prosopagnosia for years. “You can imagine if you’re an acquired prosopagnosic, well, one day you could recognize people and the next day you couldn’t. So it’s much more apparent to people.”

“I have always believed my whole life that if I could just pay more attention, I would be better at recognizing faces.”

To perceive and recognize a face, the brain relies on a neural network of at least three core regions that seem to contribute to different aspects of face processing. (There’s debate over whether or not this network is specialized for processing faces alone, or if it’s also used to discriminate among other visual objects associated with expertise, such as birds for birders.) These regions are found in the occipital and temporal lobes of both the right and left hemispheres, although the right side seems to be more active in face processing, according to neurologist Jason Barton, who runs the Human Vision and Eye Movement Laboratory at the University of British Columbia. (Barton’s team worked with Lisa Brown.)

Damage to different parts of this neural network can interrupt different aspects of the face-recognition process. For instance, work by Barton and others have shown that lesions in certain regions in the right occipital lobe can inhibit people’s ability to perceive faces—that is, faces just don’t register. “When they look at a face, they can’t see enough of the details in the face to know who that is,” says Barton. “It’s as if they’re looking at a face through a fog.”

For example, say you were to show someone with a lesion in the right occipital lobe side-by-side photos of a single face whose features have been moved around slightly in one of the pictures (see images below). She probably wouldn’t be able to tell you the difference between those images. (Writer’s note: A number of readers have commented that they cannot see the differences between the two faces. Barton says that the differences might be more subtle than what would be appear in a test administered in an experimental setting. If you’re unable to discern the differences, you do not necessarily have prosopagnosia.)*

A person with damage to the core areas of the face-processing network in the occipital lobe would have trouble seeing the difference between these two images. Courtesy of Jeffrey Corrow/Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Science, University of British Columbia, Vancouver

A person with damage to the core areas of the face-processing network in the occipital lobe would have trouble seeing the difference between these two images. (The eyes of the left face are farther apart than the eyes of the right face, and the left face’s mouth is higher than right face’s mouth). Note that an inability to discern the differences does not necessarily mean that you have prosopagnosia.* Courtesy of Jeffrey Corrow/Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Science, University of British Columbia, Vancouver

In comparison, people who have a lesion in, say, the anterior temporal lobe—an area associated with memory, and considered an extended part of the face-processing network—are relatively better at distinguishing one face from another but tend to be worse at remembering faces they’ve seen before, according to Barton.

The end result is that both types of people—those with more trouble perceiving, and those with more trouble remembering—end up in the same place: unable to recognize familiar faces. “Neither subject would know which face you had shown them—the first group because they can’t see it accurately enough, and the second one because they can’t remember it,” says Barton.

It’s less clear what causes face-blindness in people with developmental prosopagnosia.

Neuroimaging studies have suggested that there are structural and functional anomalies in the brain’s wiring, according to Barton, but there’s no consensus on a defining abnormality or genetic marker. (For this reason, the line between having developmental prosopagnosia and being simply “bad” with faces can be blurry, according to Barton. “One of the things about any kind of human ability is that we’re not all the same,” he says. “There is a distribution of ability.”)

Most people who suspect that they have developmental prosopagnosia “tend to be just self-diagnosing,” says Duchaine. A more reliable diagnosis comes only after the administration of a battery of tests, which might include one called the Cambridge Face Memory Test, which Duchaine developed with Ken Nakayama. (The test asks participants to memorize a series of individual faces and then asks them to identify the faces they saw out of three-face lineups.)
Related Segment

Oliver Sacks and ‘The Mind’s Eye’​


Prosopagnosia varies in severity, depending on the individual—that is, different people can have different degrees of difficulty recognizing and recalling faces. In a 2010 article for The New Yorker, the late neurologist Oliver Sacks—who said he had the developmental kind—wrote that he and others with “moderate prosopagnosia,” can, “after repeated exposure, learn to identify those they know best.” Lisa Brown, for instance, says that she always recognizes her wife. “It doesn’t matter if I’m expecting to see her or not,” she says. But if a neighbor were to approach her unexpectedly, she would have to sleuth out identifying clues.

At the very least, failing at face recognition is annoying. But the inability can have more serious repercussions. For instance, children with prosopagnosia “may have trouble making friends; they may have a lot of social anxiety,” says Kirsten Dalrymple, a research associate at the Institute of Child Development at the University of Minnesota. And you can imagine the potential risk of taking a kid with face blindness on a school field trip—should he get separated from his classmates, he’d have a harder time finding them.

To cope, people with prosopagnosia often develop workarounds. Some might focus on a person’s gait or posture, or a particularly distinctive feature about a face, such as a large nose. For her part, Brown says she’s “very good at identifying voices.” She also notices fashion choices (she spent many years as a seamstress), as well as glasses, piercings, and hairstyles. But if somebody changes her hair, she says, “I get lost.”

“Context also helps a lot,” adds Brown, who now works as a legal assistant. “If I approach someone at the courthouse, for example, and they’re behind the desk, I have a pretty good idea which of the three clerks I’m probably dealing with,” she says.

So is there a “cure” for face blindness?
The simple answer is no. Researchers have tried various treatment strategies with varying degrees of success and failure, but there’s no widely accepted approach. (For more on treatment efforts over the past 50 years, check out this review in Frontiers in Human Neuroscience.)

In a 2014 study appearing in the journal Brain, a Harvard-based team reported modest results in a group of 24 people with developmental prosopagnosia who completed a three-week online face-training program. The program required that the subjects place computer-generated faces into two categories based on the spacing between the eyes and eyebrows and the spacing between the mouth and nose. The more quickly and accurately they were able to complete each task, the harder the program became.

The design was based on one theory that people with normal face recognition interpret all the parts of a face at once, “in this holistic or gestalt way,” says Joe DeGutis, an assistant professor at Harvard University and first author of the paper. Some research has suggested that people with developmental prosopagnosia don’t typically view faces in this manner, so the researchers wanted to see if their training program could improve that ability.

To cope, people with prosopagnosia often develop workarounds. Some might focus on a person’s gait or posture, or a particularly distinctive feature.
At the end of the three-week period, the team tested how well participants could discriminate among new faces viewed head-on, as well as from different angles. They did not show improvement on the latter, but they showed slight but statistically significant improvement distinguishing between faces viewed from the front. And participants who had made it to more difficult levels during the online training (there were 13 of them) showed the most improvement, which suggested that accomplishing the task swiftly or at more difficult levels (the researchers aren’t sure which) contributed to their progress. The better trainees also showed the most improvement on a couple other measures used to test a “gestalt” approach to face processing, compared with the worse trainees.
While his team doesn’t know what kind of staying power the treatment will have, DeGutis is optimistic about their approach. “I think we’re showing the proof of concept that it’s possible to enhance [facial recognition]” in people with developmental prosopagnosia, he says. His team just received funding from the National Institutes of Health to launch a much bigger study to test this treatment in conjunction with neural imaging so that they can see what’s actually changing in the brain. (And if you happen to experience significant difficulties recognizing faces, live in New England, and are interested in participating in training studies, you can email DeGutis at [email protected]).

A few years ago, another team (which included Duchaine) also reported somewhat encouraging results from a randomized, placebo-controlled, double-blind study investigating how the hormone oxytocin affects face processing in participants with developmental prosopagnosia. (Why oxytocin? Research on healthy subjects has shown that nasal spray of the stuff can improve memory for social stimuli such as faces, and that the hormone increases the time spent looking at the eye region, an area important for normal facial identification.)

After inhaling either an oxytocin or placebo nasal spray, 10 participants with developmental prosopagnosia completed two face-processing tasks—one that tested memory by requiring participants to view and recall a set of faces, and another that tested perception, requiring subjects to match “like” faces. Results showed an improvement on both the face memory and the face-matching test in the group that had taken oxytocin, but not in the control group.

What’s going on? The authors noted that past research has shown that oxytocin modulates activity in a face-processing region in the occipital lobe called the fusiform face area; they suggested that increased activity in that region might have contributed to the participants’ improvements. Or, perhaps the brain’s amygdala played a role. Several studies indicate that the amygdala—which is thought to act in concert with the face-processing network—is important for mediating the effects that oxytocin has on how the brain processes social cues. Future research involving neuroimaging would be necessary to reveal what oxytocin is actually doing in the brain in people with prosopagnosia, however.

In the meantime, as Oliver Sacks put it in the New Yorker piece, “people with varying degrees of face blindness must rely on their own ingenuity, starting with educating others about their unusual, but not rare [at least with respect to developmental prosopagnosia] condition.” He noted that books, websites, and support groups are cropping up more and more, too, to help people with prosopagnosia share their experiences and recognition strategies “when the usual ‘automatic’ mechanisms have been compromised.”

*Neurologist Jason Barton says that the image of the two faces is a simulation of an experimental test but not identical to it, and so the differences between the faces might be more subtle than in a lab test. Being unable to identify the differences between the faces in this image does not necessarily mean that you have prosopagnosia. As with many human abilities, face recognition spans a spectrum of ability. This article was updated on February 19, 2016 to reflect this information.

Meet the Writer​

About Julie Leibach

@julieleibach
Julie Leibach is a freelance science journalist and the former managing editor of online content for Science Friday.

https://www.sciencefriday.com/articles/what-is-face-blindness/
 

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I think Pinky Gay Loong got this face blindness disease. He obviously cannot recognize this is a man.

ho-ching-the-executive-director-and-ceo-of-state-linked-singapore-investment-firm-temasek.jpg
 

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I rather have face blindness than breast blindness. The ability to identify a person from their neh-neh shape and size is a gift worth having.
 
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