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Iconic memory or icon? - 1
Commentary era Ralph Norman Haber (1983). The impending demise of the icon: A
critique of the concept of iconic storage in visual information processing. Behavioral and
Brain Sciences, 6:1-54.
Abstract of the original article:
Without disputing the experimental evidence that subjects have available
most of the content of brief displays for a fraction of a second, or that
visual stimuli persist after their physical termination for a similar time, I
argue that this evidence is irrelevant to perception. Specifically the notion
of an icon as a brief storage of information persisting after stimulus
termination cannot possibly be useful in any typical visual
information-processing task except reading in a lightning storm. Since the
visual world that provides the stimuli for perception is continuous and not
chopped up by tachistoscopes, and since our eyes and heads are rarely
motionless, no realistic circumstances exist in which having a frozen
iconic storage of information could be helpful. Rather, the presence of
such an icon interferes with perception. This paper examines instances of
normal perception, and then reviews experimental evidence on temporal
integration, saccadic suppression, masking, and the photoreceptor basis of
visual persistence, to further demonstrate that a storage of excitation
cannot be a useful device for storing information. Finally, I note that little
would have to be changed in our theories of visual perception or
information processing if we simply forgot all about the icon and iconic
memory as an early stage of' processing.
Iconic memory or icon?
Siu L. Chow
Department of Psychology, University of Wollongong, Wollongong, N.S.W., Australia
2500
Identifying the consequence of a brief stimulus presentation with its aftereffects on the
retinoreceptors in his target article, Haber (1983) envisages a statis (or "frozen")
two-dimensional retinal image of a stimulus (i.e., an icon). Haber further argues that this
icon cannot represent ecologically relevant information, which is predominantly
three-dimensional and temporally distributed, and that much of what we know about the
icon is irrelevant to normal perception because the data are obtained in artificial settings.
The objectives of the present commentary are to show that (1) one important theoretical
property of iconic memory is inconsistent with a retinotopic icon, (2) data difficult for the
notion of an icon do not necessarily challenge the notion of an iconic store, (3) the iconic
store, as a theoretical mechanism, is an ecologically valid one, and (4) the rationale of
experimentation is such that the experimental task need not mimic the phenomenon being
studied.