In our youth-obsessed culture, it sometimes seems that aging has become synonymous with mental decline. A new paper is challenging the idea that getting older means a slower, weaker brain. It appears that elements of social judgment and short-term memory—long viewed as abilities that peak in our 20s—may peak much later in life. The paper, based on a large study, adds fuel to an only recently kicked-off debate suggesting that the older brain slows down only because “it has to search a larger mental library of facts.”