Old age begins at 27 years of age, when the power of the mind begins to weaken, according to researchers from the University of Virginia.
They found that people's mental abilities peaked at age 22 and five years later began to deteriorate.
Professor Timothy Salthaus said that the results speak for themselves: the therapies tasked with preventing or altering age-related conditions, show that people may need to start them earlier, long before reaching retirement age.
" The results converge on the conclusion that some aspects, of age-related decline in mental abilities, begin in healthy, educated people between 20 to 30 years of age, "he added.
The study of 2, 000 men and women was carried out over more than seven years.
Respondents - between 18 and 60, were asked to solve visual puzzles, to remember words and details of specific stories and notice the differences in structures of letters and symbols.
Such tests are commonly used to diagnose mental problems, including dementia. Researchers found that the average age that had the best performance was 22, out of every 9 out of 12 tests given.
The earliest age at which performance was significantly worse, began with 27-year-olds. In other tests, poorer results were seen in 42-year-olds.
However, the study found that abilities related to the accumulation of knowledge, such as the results of tests for lexical or general information, began to decline after age 60.
The number 27 is loaded with negative perceptions, as this is the age at which a number of famous musicians, such as Jimi Hendrix, Jim Morrison, Brian Jones, Janis Joplin and Kurt Cobain died.