Aging
The process of aging remains as enigmatic as it is inevitable. And what knowledge we have gained over the years can sometimes be easily overturned. "For example, we used to believe that people became grumpy as they got older. But an analysis of long-term data from the Baltimore Longitudinal Study on Aging discovered that an adult’s personality generally doesn’t change much after age 30," says researcher Luigi Ferrucci. "In fact, people who are happy when they’re younger are likelier to be the same when they’re much older." It turns out "grumpy old men" – or women, for that matter – may be gruff not because of age, but because they’re set in a personality shaped by their youth during times when war, poverty and other harsh experiences were more common. "It also suggests that significant changes in personality may not be due to aging," says Ferrucci, "but could be a sign of disease or dementia instead."