"Going into the study, we knew that ageing changes the way people see the world," says Allison Sekuler, one of the senior authors and a Canada Research Chair at McMaster. "But these results are an unusual twist on the standard 'ageing makes you worse' story, and they provide clear insight into what is changing in the ageing brain."
Using computer-generated stimuli, the researchers monitored how much time subjects needed to process information about the direction in which a set of bars moved. When the bars were small, or when the bars were low in contrast (light gray vs. dark gray), younger subjects took less time to see the direction of motion. But when the bars were large, and high in contrast (black vs. white), older subjects outperformed the younger subjects.
"The results are exciting not only because they show an odd case in which older people have better vision than younger people, but also because it may tell us something about how ageing affects the way signals are processed in the brain" says Patrick Bennett, the other senior author, also a Canada Research Chair at McMaster.
The results suggest that as we age, the ability of one brain cell to inhibit another is reduced. That sort of inhibition helps young people find an object hidden among clutter, but it can make it hard to tune into the clutter itself. When the young brain sees big, high-contrast bars, it effectively tunes out because there is no object hidden in the bars. But older brains do not inhibit information in the same way, so they do not tune out the bars, and they can actuall
Contact: Jane Christmas