The growth of brain tissue was previously thought to stop before adulthood when neurons then create connections between each other to adapt rather than grow further.

However, a new study has revealed an area of the brain that deals with recognizing faces still keeps growing long after adolescence. The team from Stanford University lead by graduate student in neurosciences Jesse Gomez, conducted MRI scans on 22 children (aged 5 to 12) and 25 adults (aged 22 to 28) and monitored their brain activity while looking at a selection of different pictures.

The scans revealed significant changes in the fusiform gyrus which is the area of the brain that helps to tell one face from another. From looking at the scans, the team found the amount of brain tissue increased by 12.6 percent from childhood to adulthood and those with the most amount of tissue in the fusiform gyrus were better at recognizing different faces.

“This tissue development is correlated with specific increases in functional selectivity to faces, as well as improvements in face recognition, and ultimately leads to differentiated tissue properties between face- and place-selective regions in adulthood,” explained the researchers in their study.

It’s believed the reason for the increased brain tissue is the need to recognize more faces as social circles and interactions increase as we get older. When younger, we only need to remember those few friends and family members we spend time with but as we move through the world, the brain needs to adapt to the vast number of people we need to interact with.

The study also showed that the density of the brain tissue in this area begins to plateau once a person reaches around 30 years old. The research team plan to follow up with the same group of participants over time to study what happens to the brain tissue density in older adults.

Details of the study were published in the journal Science.