without any reasonable amount of training are empirically suspect. Yet, Dick (1969) did
not give his subjects any training on the partial-report task. This was particularly serious
in Dick's study in which subjects were given a small number of practice trials on the
whole-report task before being tested on the partial-report task. This methodological
feature in Dick's study gives credence to Coltheart's (1980) suggestion that Dick's
subjects might have been recalling from a more durable storage mechanism. At the same
time, it means that Dick's study cannot be used to support the hypothesis that a wrong
baseline was used in assessing the selection of category information after a brief stimulus
exposure. Moreover, there is also a conceptual problem with such a suggestion. Why
does partial report by category membership require a different baseline from partial
report by spatial location?
Admittedly, the iconic store is assumed to be a mechanism found in everyday
information-processing activities when the visual modality is involved. Yet, it has been
emphasized repeatedly that the partial-report task used in studying the iconic store is an
artificial one. A metatheoretical issue arises. How valid is it to study a behavioral
phenomenon with an artificial method? A related issue is: How relevant is our
understanding of the iconic store when such an understanding is achieved with
ecologically irrelevant methods? These are the metatheoretical questions recently raised
by Haber (1983) in his objection to the iconic store.
It must be noted that some investigators have found the partial-report task to be
ecologically relevant (e.g., Coltheart, 1983). Even if the question about ecological
validity is put aside, the iconic store can still be defended on metatheoretical grounds
against Haber's (1983) metatheoretical objection. To begin with, it is not true that, when
we study a phenomenon, we must use a task that mimics the phenomenon we are
studying (Chow, in press; Manicas & Secord, 1983). Moreover, Haber's point of view
"runs counter to scientific wisdom and practice developed over the past few milennia"
(Loftus, 1983, p. 28). For example, much of what we know about gravity is gained by
studying objects falling in near vacuums. Hence, it is important to realize that an obvious
use of some phenomenon in the real world does not traditionally constitute a necessary
condition for studying that phenomenon in the scientific laboratory. (Loftus, 1983, p. 28)
To conclude, the display-instruction compatibility and the perceptual grouping
hypotheses fail to withstand the falsification attempts provided by the present two
experiments. The methodological lesson to be learned is that, because the partial-report
task is an unusual one, subjects must be given more than token opportunity to adopt the
"select-then-process" strategy.
REFERENCES
CLARK, S. E. (1969). Retrieval of color information from preperceptual memory.
Journal of Experimental Psychology, 82, 263-266.