I DON’T KNOW WHO YOU ARE: FACE BLINDNESS
Imagine looking at the face of the person you love the most in the world, and not being able to recognize them. You hear their voice and it’s them; you get their smell and it’s them. Yet, there is a huge void where their face is supposed to be. You look at their face, but you can’t make sense of it- who is it in front of you? And even worse, when you look at mirror, you can’t even recognize yourself.
This is exactly what people suffering from prosopagnosia feel like every single day of their lives.
Prosopagnosia (also known as “face blindness”) is a perceptual disorder characterized by the inability to recognize faces. It should not be confused with a memory problem- there is no problem in the memory of these patients. Rather, this condition involves a problem of perception. A region in the brain called fusiform gyrus, which is responsible for higher processing of visual information, fails to process face stimuli properly. The fusiform gyrus involves an area called the fusiform face are (FFA) specialized for face recognition. Studies using brain imaging techniques like fMRI and EEG show that damage to the fusiform gyrus, FFA, and/or its surrounding regions results in prosopagnosia; and it is not yet a curable disorder.
The causes of prosopagnosia can be stroke, traumatic brain injury, and sometimes neurodegenerative diseases like Alzheimer’s, Parkinson’s, or Multiple Sclerosis (MS). This kind of prosopagnosia is often termed “acquired prosopagnosia”. However, it is mostly affecting people beginning at birth- so, “developmental prosopagnosia”.
Social Implications
At first sight, prosopagnosia may not hit you as a big, serious problem. What is the big deal if you can’t recognize faces, right? But that’s not the case. People with prosopagnosia suffer seriously in their social lives. Think about it: You go outside and don’t recognize anyone you see. Someone says hi to you, but you don’t know who it is — it can be someone you know, or a stranger trying to harm you. This is why social anxiety disorder is often comorbid (occuring at the same time with) prosopagnosia often. This prevents them from going out as frequently as other people, which may result in becming lonely and as a result, depressive symptoms can appear. So, prosopagnosia is not only about not being able to recognize faces; it has much more severe consequences.
The big impact of prosopagnosia on social life results from humans’ heavy reliance on face recognition beginning in early childhood. Children start recognizing faces as different from other objects as early as 6 months after birth. This is believed to have roots on evolution as face recognition, and especially recognizing familiar faces (of the caretakers, family member etc.), is adaptive for survival. Since a similar pattern of face recognition development is observed in monkeys as well, the brain regions related to face recognition are believed to have developed througout the evolutionary trajectory.
An interesting fact about prosopagnosia is that it is commonly seen in children with Asperger’s syndrome and Autism Spectrum Disorder (ASD). As you may be familiar, both of these disorders are characterized by social impairments. Thus, the presence of prosopagnosia may be a cue as to why these people have problems in social communication — because they don’t recognize who they are talking to. Eye-tracking studies of childen with ASD show that when looking at picture of humans, children with ASD do not focus on the face. Rather, they look at the hair, body, and the surrounding area of the person. This may be due to a lack of ability in recognizing the face a distinct feature of the human body. This is why special face recognition training programs are being developed and used to improve social communication skills in people with such disorders.
It should be noted that there are different types and severities of prosopagnosia. Some people only have difficulty in recognizing familiar faces whereas others don’t even recognize their own face. Some people with prosopagnosia may also have another type of agnosia that prevents them from recognizing objects (apperceptive visual agnosia) or places/locations (Balint’s syndrome).
The fact that this is a disorder that has no cure makes it even harder on people suffering from it. However, these people come up with other methods to recognize people. The most frequently used cues involve recognition from hair (style or color), voice, and clothes. Although these are not nearly as good enoguh faces, they are the only option with people with prosopagnosia.
References
Corrow, S. L., Dalrymple, K. A., & Barton, J. J. (2016). Prosopagnosia: current perspectives. Eye and brain, 8, 165. doi: 10.2147/EB.S92838
Nelson, C.A. (2001). The development and neural bases of face recognition. Infant and Child Development, 10(1–2), 3–18. doi: 10.1002/icd.239
