Eyesight improves when people expect to have especially keen vision
By Bruce Bower / Source: Science News
Imagine seeing better by thinking differently. That's a vision with a
future, according to Harvard University psychologist Ellen Langer.
Eyesight markedly improved when people were experimentally induced to believe that they could see especially well, Langer and her colleagues report in the April Psychological Science.
Such expectations actually enhanced visual clarity, rather than simply
making volunteers more alert or motivated to focus on objects, they
Langer's new findings build on long-standing evidence that visual
perception depends not just on relaying information from the eyes to the brain but on experience-based assumptions about what can be seen in particular situations. Those expectations lead people to devote limited attention to familiar scenes and, as a result, to ignore
unusual objects and events.
In perhaps the most eye-popping of Langer's new findings, 20 men and
women who saw a reversed eye chart — arranged so that letters became progressively larger further down the chart, with a giant "E" at the bottom — accurately reported more letters from the smallest two lines than they did when shown a traditional eye chart with the big letters on top. All volunteers had normal eyesight.
These results reflect people's expectation, based on experience with standard eye charts, that letters are easy to see at the top and
become increasingly difficult to distinguish on lower lines, the
Participants who said they thought that they could improve their
eyesight with practice displayed a bigger vision boost on the reversed
chart than those who didn't think improvement was possible, but only
for the next-to-smallest line. Both groups did equally well at reading
the smallest, topmost line.
Another set of experiments included 63 members of the Reserve
Officers' Training Corps at MIT. Eye testing determined that their
vision ranged from below average to excellent.
An experimenter told a group of 22 cadets to assume the role of a
fighter pilot while operating a flight simulator. During this exercise, participants tried to identify letters shown on four plane wings of approaching aircraft. Each wing contained one of the bottom
four lines of an eye chart.
Another 20 cadets performed the visual task while pretending to fly a
plane in a simulator that they were told was broken. Ten other cadets
read a motivational essay before the exercise. A final group of 11
cadets didn't use a simulator but practiced eye exercises that
researchers described as capable of improving eyesight before taking
an eye test.
Vision improved substantially for nine of 22 simulator pilots compared
with none of those who pretended to fly, two of 11 eye exercisers and
one person in the motivational group. Simulator pilots did so well
relative to the others because they more thoroughly adopted a mind-set
of being real fighter pilots with presumably superior vision, the
researchers posit. An initial survey of ROTC members found that they
attributed particularly good vision to fighter pilots.
Simulator pilots with below-average vision displayed the biggest jumps
in visual performance, perhaps because they had more room for
improvement, the researchers suggest.
These results suggest that if eye exercise programs designed to
improve vision work for some people, it's not because of any physical effect on the eyes or brain. Such regimens "may be effective because they prime the belief that exercise improves vision," Langer and her colleagues write.
Mind-set may boost visual performance without sharpening vision itself, comments psychologist Daniel Simons of the University of
Illinois at Urbana-Champaign.
Experimental manipulations in the new study, such as reversing the
arrangement of an eye chart, may have made volunteers more willing to guess when they felt a bit unsure, Simons says. Such guesses stand a
good chance of being right, in his view.
Edited by: Lawyer Asad