It has been argued that faces are a special type of stimuli, which we are able to process easier than other items in the environment. For example, young infants prefer to look at features forming a face, rather than scrambled features (e.g., Johnson & Morton, 1991), which suggests that we have this enhanced ability to process faces from birth. Thomas (1980) argued that faces are processed more holistically than other objects. But how are faces processed in the brain?
One hypothesis is that there is a special area in the brain for processing faces – the Fusiform Face Area located in the fusiform gyrus (shown below). This was named by Kanwisher (1997) in a fMRI study which found that this area was more active in participants when they viewed faces, rather than other stimuli. It also showed more activity for whole faces, rather than scrambled ones. They therefore concluded that this cortical area is specialised for processing faces.
Further evidence for this area being specialised for face perception is shown by patients with prosopagnosia – an inability to recognise faces. One of the causes of this disorder is damage to the FFA and surrounding cortical areas, which suggests this area is important for normal face perception.
However, although this area might be important for face perception, there is evidence from patients with damage to the FFA who have no trouble detecting faces (e.g. Tranel et al, 1998). Therefore, the FFA might not be necessary for face perception. Some studies have also suggested that the FFA alone isn’t sufficient for normal face perception. Behrmann (2003) found that patients who had prosopagnosia from birth (not from neurological damage) had intact FFA and normal activity there. This evidence suggests that things might be a bit more complicated than simply having one area which is responsible for face perception.
One alternative explanation is that there is a network of cortical areas, which all interact to process faces (Haxby, 2000). This study used a pattern analysis method and found that several other areas in the brain were active when participants were shown pictures of faces e.g. the superior temporal sulcus and lateral occipital gyri, suggesting the theory of a single area such as the FFA is over-simplified.
I hope you enjoyed this post, and thank you for reading.