8. For the ability to evaluate other people’s emotional states, the peak occurred much later, in the 40s or 50s. Christopher Chabris, an associate professor of psychology at Union College, said a key feature of the study’s success was the researchers’ ability to gather and analyze so much data, which is unusual in cognitive psychology.
“You need to look at a lot of people to discover these patterns,” says Chabris, who was not part of the research team. “They’re taking the next step and showing a more fine-grained picture of how cognitive abilities differ from one another and the way they change over time.”
More work will be needed to reveal why each of these skills peaks at different times, the researchers say. However, previous studies have hinted that genetic changes or changes in brain structure may play a role. “If you go into the data on gene expression or brain structure at different ages, you see these lifespan patterns that we don’t know what to make of. The brain seems to continue to change in dynamic ways through early adulthood and middle age,” Germine says. “The question is: What does it mean? How does it map onto the way you function in the world, or the way you think, or the way you change as you age?” 
Accumulated intelligence