People who are blind from birth use the same part of the brain to recognise faces as those with normal vision. This suggests humans have evolved with innate facial identification abilities, the authors of a new study say.

Scientists have long debated whether brain regions that deal with facial identification are hard-wired or develop in response to experience.

Researchers at the Georgetown University Medical Center in Washington DC trained volunteers to use a device that translates simple shapes captured on a head-mounted camera into different sounds (Plaza et al, 2023).

Six individuals who had been blind either from birth or by the age of two and 10 sighted controls with blindfolds learnt to identify basic images of faces, houses and geometrical shapes using the device.

When tested during functional MRI scans, greater activation in the fusiform face area (FFA) – believed to be involved in facial recognition – was seen in the brains of participants in both groups in response to faces than to other images.

Author Paula Plaza said the research showed the FFA handled the concept of faces rather than just images of them.

In blind subjects, brain activity occurred primarily in the left FFA; in sighted subjects in the right FFA. Previous research has found that the left FFA handles identification of facial components while the right processes information about whole faces.

It may be that the representations of faces were more similar to each other than those of other shape, and that the FFA activation was a response to their similarity or another factor unrelated to their face-like properties.

Facial recognition is a multifaceted task involving multiple brain regions (Lopatina et al, 2018 ). Determining the degree to which it is hard-wired or learnt requires more detailed research.