Provided by Cognitive Sciences ePrint Archive
Iconic Memory, Location Information, and Partial Report
Siu L. Chow
University of Wollongong, Wollongong, New South Wales, Australia
It has been suggested that the systematic decline of partial report as the
delay of the partial-report cue increases is due to a time-related loss of
location information. Moreover, the backward masking effect is said to be
precipitated by the disruption of location information before and after
identification. Results from three experiments do not support these claims
when new indices of location information and of item information are
used. Instead, it was found that (a) the systematic decline in partial report
was due to a time-related loss of item information, and (b) location
information was affected neither by the delay of the partial-report cue nor
by the delay of backward masking. Subjects adopted the
"select-then-identify" mode of processing.
Iconic memory, as a hypothetical mechanism, has an interesting and controversial
history. Although its empirical foundation was established by Sperling (1960), it was so
named by Neisser (1967) and integrated into the information-processing approach to
perception by Haber (1969, 1971; Haber & Hershenson, 1980). However, its importance
is no longer recognized by Neisser (1976). Furthermore, its theoretical usefulness is now
seriously questioned by Haber (1983) on metatheoretical grounds (in addition to other
reasons). A metatheoretical rejoinder to Haber's (1983) metatheoretical argument has
been offered by Loftus (1983) and Chow (in press).
At the theoretical level, iconic memory has been identified with (a) a kind of
visible persistence that renders phenomenological report possible (Haber & Nathanson,
1968; Haber & Standing, 1969), (b) the aftereffects of stimulating the retinal rods (Sakitt,
1975, 1976a, 1976b), and (c) some sort of precategorical representation called
"informational persistence" by Coltheart (1980). This article is concerned with the
empirical foundation of iconic memory in the sense of informational persistence.
The empirical foundation of informational persistence is not without dispute. For
example, Holding's (1970, 1972, 1975) critique of Sperling's (1960) partial-report
paradigm in terms of some probable procedural artifacts, such as guessing and response
selection, has been dealt with by Coltheart (1975, 1980). Merikle's (1980) questioning of
the partial-report paradigm in terms of perceptual grouping has been answered by Chow
(1985). It is necessary now to consider Mewhort and Butler's (1983) contention that the
empirical basis of iconic memory is not sound in view of some findings by Mewhort and
his associates (Campbell & Mewhort, 1980; Mewhort & Campbell, 1978; Mewhort,
Campbell, Marchetti, & Campbell, 1981).