Perceptual Science Series
Long-lasting sensitization to color based on attention
Monday, November 29, 2004, 02:00pm - 03:00pm
RuCCS, Lab of Vision Research
It is well known that attention enables us to selectively process useful visual information in both daily life activities and lab-designed behavior tasks. To cope the variable challenges, attention is known to be short-duration and quickly reversible. But we don�t know if attention also has long-duration properties � it was never reported before probably because of the lack of a good measurement of the lasting effect. In this talk, I will first describe an ambiguous motion display as a novel measurement of attention. The display is an isoluminant grating composed of red and green stripes alternating with a texture grating. The perceived direction of this motion sequence depends both on the attended color and on the relative saturation/salience of the composing colors, red and green. That is, attending to an unsaturated red stripe causes it to behave�in the motion sequence�like a more saturated red stripe. The change in motion perception is a very sensitive assay of attention. This enabled us to discover a long-lasting sensitization based on attention. When a subject is trained for a few days, for about an hour each day, to search for an object of a particular color, sensitivity to that color is altered for weeks, and in some cases, for months. This prolonged alteration in sensitivity is surprising and unexpected, and poses a well-defined puzzle for perceptual and neural scientists.