Are We Getting Old At 27?

By Margarita Nahapetyan

New findings of the US scientists suggest that people reach their peak of cognitive abilities and mental performance at the age of 22 years, before beginning to deteriorate from the age of 27.

The study was performed by Professor Timothy Salthouse of the University of Virginia, who studied 2,000 men and women with the ages between 18 and 60 years, over a seven year period of time. The majority of the participants were in good health and well-educated. For the experiment, they were asked to solve visual puzzles, recall words and story details, as well as spot patterns in letters and symbols - tasks similar of those that are used to detect dementia.

Prof. Salthouse found that some aspects of mental performance peaked around age 22, but that there was noticeable decline in brain speed around the age of 27. The decline happened in speed of thought, reasoning and spatial visualization, or ability to visualize and solve puzzles and problems. The results revealed that in 9 out of 12 tests, participants at the age of 22 performed the best, and those after the age of 27 showed consistently poorer results. In the other tests, poorer results were shown by the age of 42.

However, other areas of cognitive ability did not deteriorate so early, reported the researchers. Salthouse found that there were no changes in memory until around the age of 37, and other things like abilities that rely on accumulated knowledge, such as performance on tests of vocabulary or general information, increased until the age of 60.

Salthouse wrote that cross-sectional studies have consistently shown that increased age is associated with decreased levels of mental or cognitive abilities, even in individuals with the ages between 18 and 60. However, many people doubt the validity of using cross-sectional studies, which investigate age related issues, because they compare differently aged people and do not compare people against themselves as they get older. The scientist brought an example of longitudinal studies that retest people as they get older.

But this, in turn, can also cause problems because if retesting is being performed on the same people, it will be hard to separate out any effects that might appear, as people will already know what to expect in the tests and will try to do their best next time while performing. Such effects could hide any results from longitudinal studies that might show a lower inclination for cognitive decline with age, which is what Salthouse found: "The results of the current project suggest that a major factor contributing to the discrepancy is the masking of age-related declines in longitudinal comparisons by large positive effects associated with prior test experience," he said.

The scientist added that when he combined the results from three ways of estimating the effects of retesting people, with the results from previous studies that compared animals raised in constant environments, and other research that looked at neurobiological variables that are not susceptible to the retesting effect, he concluded that: "Some aspects of age-related cognitive decline begin in healthy educated adults when they are in their 20s and 30s."

The study is published in the April issue of the journal Neurobiology of Aging.