Search Here

As people grow older, their physical and mental capabilities start to decline. In a new study, researchers set out to uncover why intelligence declines with age. They found that as people grow older, their visual perception speed starts to decline, which was then related to age-related declines in intelligence.

For this study, the researchers examined the health of 600 older adults. In order to measure visual perception speed, the participants were shown two pictures, one at a time. The researchers recorded how long it took the participants to reliably differentiate one picture from the other. The tests were conducted when the participants were aged 70, 73 and 76.

"The results suggest that the brain's ability to make correct decisions based on brief visual impressions limits the efficiency of more complex mental functions. As this basic ability declines with age, so too does intelligence. The typical person who has better-preserved complex thinking skills in older age tends to be someone who can accumulate information quickly from a fleeting glance," stated Stuart Ritchie of the University of Edinburgh according to the press release. "What surprised us was the strength of the relation between the declines. Because inspection time and the intelligence tests are so very different from one another, we wouldn't have expected their declines to be so strongly connected."

The team noted that in other studies, researchers had concluded that people with higher intelligence quotients (IQ) were faster at telling two shapes apart when the shapes were presented quickly on screen. This study adds more evidence that visual perception speed is linked to intelligence.

Ritchie added, "Since the declines are so strongly related, it might be easier under some circumstances to use inspection time to chart a participant's cognitive decline than it would be to sit them down and give them a full, complicated battery of IQ tests."

The study, "A strong link between speed of visual discrimination and cognitive ageing," was published in the Cell Press journal, Current Biology.