Genes May Guide Intelligence Throughout Life, University of Edinburgh Study  
1/19/2012 7:13:19 AM

Most people have met some 65-year-olds who aren't as "with it" as they once were, and some 90-year-olds who are still sharp as a whip. What accounts for the differences? Using a genetic analysis and intelligence tests taken in a group of people in childhood and old age, researchers concluded both genes and environmental factors play a role in whether you'll maintain your level of intelligence throughout your lifespan.