A new research shows how intelligence of certain people declines with age. Researchers said that as people age, their visual perception speed begins to decline, resulting into age-related declines in intelligence.
The study was conducted on 600 older adults. The researchers measured the visual perception speed by showing two pictures to the participants. Each image was shown at a time. The team recorded the time the subjects took to 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," Stuart Ritchie of the University of Edinburgh said in a press release.
He said that the surprising aspect of the study findings 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," Ritchie said.
Researchers said that previous studies found that people with higher intelligence quotient were faster at telling two shapes apart after being presented quickly on screen. This current findings strengthens the observations that visual perception speed is linked to intelligence.
"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," Ritchie said.
The study, 'A strong link between speed of visual discrimination and cognitive ageing,' was published in the Cell Press journal, Current Biology.
