Secret behind bad driving by elderly unraveled
Failure to block out irrelevant background motion, and not poor reflexes, is the reason why older people, patients of depression and schizophrenia are poor drivers, shows new research by American scientists. Charu Sudan Kasturi reports.health and fitness Updated: Jan 26, 2011 09:47 IST
Reduced ability to ignore irrelevant background objects on the road is the reason why older people struggle to drive, scientists have found, busting popularly held myths and offering a possible signal for select mental illnesses.
Contrary to popular belief, age enhances awareness of backdrops against which objects move, the scientists at the University of Rochester have found, arguing that this leads to older people failing to focus adequately on nearer, more relevant motion.
The scientists, who performed their research at the Harvard Medical School’s Berenson-Allen Center for Noninvasive Brain Stimulation, have reported their surprise findings in the Journal of Neuroscience published on Tuesday.
The middle temporal visual area – commonly referred to as the MT – of the brain suppresses irrelevant background motion in young, healthy people, allowing them to focus on the more important motions of smaller objects in the foreground.
“Evolutionarily speaking, moving objects are the most important visual features to detect quickly, because they could be your lunch or they could want to eat you for lunch. It makes sense that our vision prioritizes processing them,” Duje Tadin, lead author of the research and professor at the University of Rochester said.
The amount of visual information around us is huge, and we don’t have the brain power to process it all, Tadin said.
Using electrical signals, the scientists stimulated the MT of selected subjects to temporarily inhabit its functioning. They found that the subjects with inhibited MTs had an easier time identifying large, background objects, indicating that an improperly functioning MT may be responsible for older persons struggling to focus on smaller objects in the foreground.
The scientists have argued that since patients suffering from schizophrenia or depression also have inhibited MTs, their findings could provide a new approach to tackling these illnesses.
The research findings also show how older people need to be trained to counter their aging MTs, the scientists have said.