STROOP CAN OCCUR WITHOUT GARNER INTERFERENCE - STRATEGIC AND MANDATORY INFLUENCES IN MULTIDIMENSIONAL STIMULI

Stroop and Garner interference were studied in two experiments involvi ng stimuli with several irrelevant features. Using these stimuli, whic h were more complex than those usually used in perceptual interference studies, a new phenomenon occurred: Stroop effects without a correspo nding Garner interference were obtained in four out of six nontarget c onditions, two with local and two with global targets. The effects wit h local targets were anomalous: on one dimension, incongruous Stroop s timuli were better than congruous ones, while on the other dimension, effects were restricted to a condition in whichh all nontargets were c ongruous. With global targets, more consistent cases of Stroop-without -Garner effects were obtained. All Stroop effects were replicated in E xperiment 2, in which presentation time was varied. The effects showed a strong dependency on presentation time, in such a way as to suggest a dynamic growth of the percept. The results were interpreted in term s of an interaction between automatic and strategic components of perc eptual processes, in agreement with a recently introduced perceptual-o rganization model, which yields a new interpretation of priming and in terference phenomena.