norman%ics@UCSD.EDU (Donald A Norman-UCSD Cog Sci Dept) (11/16/88)
Iconic memory is the brief, reasonably veridical image of a sensory
event. In the visual system, it has a time constant of somewhere
around 100 msec. Visual iconic memory is what makes TV and motion
pictures possible: 30 to 60 images a second fuse into a coherent,
apparently continuous percept. I demonstrate this in class by waving
a flashlight in a circle in a dark auditorium: I have to rotate about
3 to 5 times/second for the class to see a continuous image of a
circle (the tail almost dying away).
The illustration of seeing complementary colors after staring at, say,
an image of a flag, is called a visual after effect, and is caused by
entirely different mechanisms.
don norman
Donald A. Norman [ danorman@ucsd.edu BITNET: danorman@ucsd ]
Department of Cognitive Science C-015
University of California, San Diego
La Jolla, California 92093 USA
UNIX: {gatech,rutgers,ucbvax,uunet}!ucsd!danorman
[e-mail paths often fail: please give postal address and all e-mail addresses.]