My toddler son can always recognize my face and my husband's, but sometimes it seems to take him a bit to recall the babysitter he hasn't seen for a week or a family member gone for several months. Perhaps, as a pair of new studies show, that's because he hasn't yet grown the tissue in the facial recognition area of his brain.
The finding that any growth at all occurs is worth noting. Previously, researchers assumed that brain development progressed from excessive tissue and neural connections at birth to a leaner, more honed brain in adulthood. A recent Stanford News article explains how the discoveries were possible because the researchers studied the brains of children:
'I would say it’s only in the last 10 years that psychologists started looking at children’s brains,' said Kalanit Grill-Spector, [PhD] a professor of psychology at Stanford and senior author of both papers. 'The issue is, kids are not miniature adults and their brains show that. Our lab studies children because there’s still a lot of very basic knowledge to be learned about the developing brain in that age range.'
Grill-Spector and her team examined a region of the brain that distinguishes faces from other objects. In Cerebral Cortex, they demonstrate that brain regions that recognize faces have a unique cellular make-up. In Science, they find that the microscopic structures within the region change from childhood into adulthood over a timescale that mirrors improvements in people’s ability to recognize faces.
'We actually saw that tissue is proliferating,' said Jesse Gomez, graduate student in the Grill-Spector lab and lead author of the Science paper. 'Many people assume a pessimistic view of brain tissue: that tissue is lost slowly as you get older. We saw the opposite – that whatever is left after pruning in infancy can be used to grow.'
The team also used an innovative technique to get a glimpse of the cellular structures in the facial recognition area of the brain in living tissue.
Grill-Spector, for one, is excited about the findings:
If you had told me five or 10 years ago that we’d be able to actually measure tissue growth in vivo, I wouldn’t have believed it... It shows there are actual changes to the tissue that are happening throughout your development. I think this is fantastic.
Previously: One patient can still spot faces post-surgery, suggesting perception network is resilient, Face blindness stems from differences in neurocircuitry and In a human brain, knowing a face and naming it are separate worries
Photo by Brianna Jeska