Professor Timothy Salthouse said the results suggested that therapies designed to prevent or reverse age-related conditions may need to start earlier, long before people become pensioners.
Almost half of over 50s 'unaware of leading cause of blindness'" Results converge on a conclusion that some aspects of age-related cognitive decline begin in healthy, educated adults when they are in their 20s and 30s," he said.
The study of 2,000 men and women lasted over seven years. The respondents, aged between 18-60, were asked to solve visual puzzles, recall words and story details and spot patterns in letters and symbols.
Similar tests are often used to diagnose mental disabilities and declines, including dementia.
The research by the University of Virginia found that in nine out of 12 tests the average age at which the top performance was achieved was 22.
The first age at which performance was significantly lower than the peak scores was 27 – for three tests of reasoning, speed of thought and spatial visualisation. Memory was shown to decline from the average age of 37. In the other tests, poorer results were shown by the age of 42.
However, the report published in the academic journal Neurobiology Of Ageing, found that abilities based on accumulated knowledge, such as performance on tests of vocabulary or general information, increased until at the age of 60.
Twenty-seven has long had negative connotations, as it is the age at which many popular musicians died, including Jimi Hendrix, Jim Morrison, Brian Jones, Janis Joplin and Kurt Cobain.
27岁一直是个不太吉利的年龄，很多流行歌手在27岁时去世，其中包括吉米 亨德里克斯、吉姆 莫里森、布赖恩 琼斯、贾尼斯 乔普林和柯特 科本。
visual ['vizju l]adj. 视觉的，视力的;栩栩如生的
dementia n. 痴呆