Some research suggests that exercising your brain by doing crossword puzzles or learning new skills can sharpen your thinking skills. But simply interacting with people may be at least as effective, according to two studies from the University of Michigan published in February 2008. The first study, involving more than 3,600 adults, found that regardless of age, the more frequently they interacted with friends, neighbors, and relatives, the higher their score on a simple test of cognitive function.

The second experiment, conducted in a group of about 75 young adults, found that discussing a social issue for 10 minutes before taking a test boosted performance as much as engaging in intellectual tasks such as working a crossword puzzle.

Socializing may also play a role in keeping you sharp as you age. Studies suggest that having satisfying relationships with friends and family and participating in mentally stimulating activities with others is associated with a reduced risk of cognitive decline and dementia.