In humans and primates, the ability to recognize faces has long been considered to be innate. This means that, from birth, the brain is “naturally” able to identify faces. But this innate view has been called into question by a recent study carried out by Harvard Medical School and published in Nature Neuroscience. What if facial recognition was actually a product of experience?

Studies on primate brain development indicate that the clusters of neurons responsible for facial recognition develop in the superior temporal sulcus at about 200 days. The region appears in various species of primates as well as humans. To better understand how the ability to recognize faces develops, Margaret S. Livingstone and her colleagues studied two groups of monkeys raised in two different ways. The first (control) group of 4 subjects received a typical upbringing. The baby monkeys spent time with their mothers and with other subjects of the same age as well as humans. The second group of 3 subjects were raised exclusively by humans whose faces were hidden by a welding mask; they fed the baby monkeys and played with them.

When the young monkeys in each group reached 200 days, the researchers examined their brains (fMRI scans). In the control group, they observed clusters of neurons associated with recognizing faces, as well as hands, objects, bodies, etc. In the group raised without any exposure to faces, these same clusters were identified, with the exception of facial recognition. The scientists then showed the two groups images of primates and humans. While the monkeys in the control group focused more on the faces, those in the second group largely focused on the hands. In addition, the “clusters” targeted by hand recognition were significantly larger in the subjects of this group. Sensory deprivation could therefore affect how the brain develops. When exposed to the same “images” on a constant basis, the brain finally implements systems adapted to these repeated contexts.

The results of this research cast doubt on the idea that we are born with the ability to recognize faces. The influence of early life experiences on our senses and brain development appear to be crucial. To this end, the authors of this study believe that a lack of early exposure to faces (weak visual stimuli) could be an interesting avenue of research to consider in order to better understand certain disorders such as autism and prosopagnosia (the inability to recognize familiar faces and even sometimes one's own face).