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No two faces are the same

No two faces are the same Important details revealed in the search for the causes of face blindness

For the very first time, researchers have been able to show that the causes of congenital face blindness can be traced back to an early stage in the perceptual process. These findings are crucial, not just for our understanding of face recognition, but also because they allow us to understand the processes behind the recognition of any visually presented object.

Each face is unique and forms a crucial part of a person’s identity and interpersonal communication. It is the unique details of our facial features that allow us to recognize one another.

However, the situation is different for people with congenital prosopagnosia, or face blindness. People affected by this condition are unable to use facial features to identify the person in front of them. In everyday life, people with facial blindness are often able to compensate for this inability to recognize others by instead focusing on, for example, a person’s characteristic appearance, hair style, or gait.

However, the true extent of the impairment becomes evident in social situations, when the affected person has to interact with others, or when the nature of their job (e.g. as a teacher or police officer) means they have to be able to distinguish between and identify many different people. It is estimated that approximately one to two percent of people are affected by this condition.

Until now, the cause of facial blindness was assumed to be associated with the later stages of the perceptual process. These are the stages involved in converting facial information into abstract code for long-term storage. A team of researchers led by Dr. Andreas Lüschow, who heads the Cognitive Neurophysiology Working Group (AG Kognitive Neurophysiologie, Klinik für Neurologie mit Experimenteller Neurologie) have been focusing their efforts on a group of persons who have experienced severe problems recognizing familiar faces from a young age, but show no evidence of other cognitive impairments.

‘”We were able to show that even the earliest face-selective responses, those recorded approximately 170 milliseconds after seeing a face, are altered in people with congenital prosopagnosia; we were also able to show that these changes are closely linked to their deficit in recognizing faces,” says Dr. Lüschow.

Researchers used MEG (magnetoencephalography) to measure the magnetic signature of cortical activity. Results showed that even life-long contact with other people does not enable affected persons to compensate for this face recognition deficit. This would suggest that the underlying neural mechanisms are divided into distinct, closed units, making it impossible for other areas of the brain to take over their function. One of the main aims of future studies will be to further define the interplay that may exist between different mechanisms.

A better understanding of cognitive processes is not only important in the field of medicine, but also in other areas of research, such as robotics, where such knowledge may be able to provide ‘biological inspiration’ for the development and improvement of technological systems.

Sources:
Lueschow, A., Weber, J., Carbon, C., Deffke, I., Sander, T., Grüter, T., Grüter, M., Trahms, L., & Curio, G. (2015). The 170ms Response to Faces as Measured by MEG (M170) Is Consistently Altered in Congenital Prosopagnosia PLOS ONE, 10 (9) DOI: 10.1371/journal.pone.0137624

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One response

  1. Lisa Beard

    I find it so interesting that the unique features of a person’s face can make all of the difference. If you think about it, it is really interesting that people can often distinguish between faces of identical twins when they know them well even though their faces look identical, even the slight blemish or detail can be used to differentiate two people. I can’t even imagine what it would be like to have a condition where I was unable to pick up on these subtle differences and recognize faces.
    I work with a lot of different people in my life and have to know a wide range of faces and names and not having that innate ability would make my job virtually impossible. Whether prosopagnosia results from brain damage or developmental problems, it seems like it would be very a very difficult condition to have in our social world. I suppose if it were caused by developmental problems this might actually be better than brain damage later in life because you might not realize what it is like not to have the condition if you yourself don’t have anything to compare it to.
    It is interesting how the people who suffer with disorder learn other ways to identify people. For example, you mentioned recognizing people by hairstyle, but hairstyle is something that frequently changes so that could lead to a lot of error and potentially be problematic. Since it is impossible for other areas of the brain to take over this function even after long exposure to a person, this seems like it would be a very difficult thing to overcome.
    Newborns come into the world born to recognize and become interested in faces, so it seems as though as this is something that is very central to human nature at its core, it would be something that really needs a lot of research done in the way of coming up with a cure or solution to the problem. I am happy to hear that more research is being done on this subject! It is very troubling to me to think of how unaware people are of this condition.
    In my life, I have only heard of one person who had trouble distinguishing faces from one another, and I don’t think his condition was as severe as what you are talking about here. I know that people who have this disorder are not lacking in visual acuity as they are able to read and write, and can remember things like voices and hairstyles so this is a reminder that memory is not the problem at play here either. The fact that someone could have the sole problem of not recognizing a face when everything else is in check is absolutely astounding.
    I have read that the fusiform gyrus is often cited as a possibly being responsible because of its association with facial responses and this seems to indicate even farther how important facial recognition is in our culture. Do you know of any specific treatments or ideas of treatments that have been brought into question for people suffering with prosopagnosia? I would love to see a blog post on research for that! The occipital face area and temporal cortex are also important for facial recognition, so it would be interesting to see if research targeting these specific areas might find any answers for this. As this post indicates, they were not able to find that there was a connection with other areas of the brain that could take over recognition of faces, so it is important to target the areas that we know do, but this also again shows how distinct facial recognition is from all other types of recognition.

    February 28, 2017 at 1:04 pm

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