Failures in visual short-term memory of objects, what scientists call "iconic memory," could reveal people at risk of Alzheimer's disease, a new study finds. Iconic memory is the image that lingers in the mind's eye after a person sees something briefly.
To find out whether iconic memories are lost more readily in people with mild cognitive impairments—which include slightly diminished capacity to solve problems and keep track of time—researchers tested 11 study participants with such deficits and 16 without them. The average ages of the two groups were 85 and 77 years.
The researchers asked each participant to recall letters arrayed in a circle and flashed momentarily on a screen. Up to 10 seconds after the image had disappeared, an arrow cued the participant as to which letter to recall.