Congenital prosopagnosia, or face blindness, a condition in which people are unable to recognize others by their facial features, can be traced back to an early stage in the perceptual process, according to a new study.
Until now, the cause of facial blindness was thought to be associated with the later stages of the perceptual process, when facial information is converted into abstract code for long-term storage.
The new findings are important, not just for our understanding of face recognition, but also because they help shed light on the processes behind the recognition of any visually presented object.
Each person’s face is a vital distinguisher of identity, as we recognize one another based on the unique details of our facial features. The situation is very different, however, for those with face blindness. It is estimated that approximately one to two percent of people are affected by this condition.
People with face blindness are often able to compensate for this inability to recognize others by instead focusing on, for example, voice, hair style, or the way they walk. This becomes more difficult, however, in social situations or when the nature of the person’s job (e.g. as a teacher or police officer) means they have to be able to distinguish between and identify many different people.
For the study, the researchers focused their efforts on a group of individuals 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,” said Dr. Andreas Lüschow of Charité – Universitätsmedizin Berlin.
Using MEG (magnetoencephalography), the researchers measured activity in the brain’s cerebral cortex. The findings show that even life-long contact with other people does not enable affected persons to compensate for this face recognition deficit. This suggests 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.
The researchers plan to conduct more studies to help them better understand the interplay that goes on between the various neural mechanisms. A better understanding of these 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.