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In season 1 episode 2 of my Secrets of the Brain series I explored how our brains process faces (also available on Curiosity Stream).
I met a very interesting man who couldn’t recognise faces, even those of his own family, a condition known as prospagnosia or face blindness.
An interesting study, recently published in the journal Cerebral Cortex and covered by this Neuroscience News article investigated how familiarity with faces influences how our brains recognise, or fail to recognise, individual faces.
They ran the study twice; once with a clever pair of studies involving neurotypical participants with no difficulties with facial recognition and again prosopagnosic participants. Their brains were scanned using fMRI while they watched excerpts from Game of Of Thrones and in both cases half the group were familiar with Game of Thrones and half had never watched it.
It revealed that when we are viewing familiar faces a wide range of brain areas are share information in order to bring to mind their character traits, past behaviours, relationship with other characters and various other aspects of our pre-existing knowledge about them as well as brain areas well known to be involved in processing the visual appearance of faces per se.
In prosopagnosic individuals this extra brain activation was significantly attenuated, presumably because the disruption to visual face processing leaves them without the critical part of the neural network on which to anchor this extra information (i.e. the “face” area in the below diagram on the underside of the brain towards the back of the head – i.e. on the fusiform gyrus).
The prosopagnosic man I interviewed in Secrets of the Brain mentioned that to recognise his own wife he’d have to use different sensory clues – such as tone of voice or distinctive items of clothing. This suggested to me at the time that rather than a decrease in the level of activity in brain areas outside of the traditional face processing areas, there would be an increase – reflecting these compensatory techniques typically employed by people living with this condition. But that’s exactly why this research is so interesting. It has put hypotheses to the test and accumulated evidence that moves the needle in one direction or another; in this case leading me to believe my assumptions back then were incorrect. Now I know better. And so the wheel of neuroscience research, continuously enlightening us on the mysteries of our own brains, continues to turn.
Great to see studies using such “natural viewing” experiences that are much closer to real life scenarios of facial recognition rather than the usual long sequences of still photographs that were so popular in recent decades when this kind of research is undertaken..
Bravo to authors Noad, Watson and Prof Tim Andrews at the University of York for pulling off such a fascinating and labour intensive study!
