NEW YORK (Reuters Health) – Declining mental function is often seen as a problem of old age, but certain aspects of brain function actually begin their decline in young adulthood, a new study suggests.

The study, which followed more than 2,000 healthy adults between the ages of 18 and 60, found that certain mental functions -- including measures of abstract reasoning, mental speed and puzzle-solving -- started to dull as early as age 27.

Dips in memory, meanwhile, generally became apparent around age 37.