Universität Bielefeld - Sonderforschungsbereich 360
How to Disregard Irrelevant Stimulus Dimensions:
Evidence from Comparative Visual Search
Marc Pomplun, Elena Carbone, Lorenz Sichelschmidt,
Boris M. Velichkovsky and Helge Ritter
Abstract
Are subjects able to (at least partially) disregard stimulus dimensions that
are irrelevant to a certain task? Do the conditions of such ignorance processes
differ between color and form? These questions were tackled in three experiments
using the paradigm of comparative visual search. the subjects' task was to compare
tow display halves that contain simple geometrical objects of three different colors
and forms. The two halves were identical except for a single difference in the color
or form of two corresponding objects. Reaction times and eye-tracking data were
recorded in order to study the cognitive processes in comparative visual search. In
Experiment 1, the subjects were not informed whether the target differed in color
or form. Therefore, both stimulus dimensions had to be attended to. In Experiments
2 and 3, experimental conditions were manipulated in a way that allowed subjects
to ignore the irrelevant dimension. Subjects were informed about the relevant
dimension either verbally (top-down) or by holding constant the type of difference
(bottom-up). The results show that on the basis of top-down processes only,
it is easier to ignore form, and that the ignorance of color requires additional
bottom-up processes.
Postscript-File (~ 159 k)
Anke Weinberger, 1998-07-20, 1999-02-16