LIMITS ON THE APPLICATION OF ADDITIVE FACTORS LOGIC - VIOLATIONS OF STAGE ROBUSTNESS SUGGEST A DUAL-PROCESS ARCHITECTURE TO EXPLAIN FLANKEREFFECTS ON TARGET PROCESSING

This study aimed to establish whether the logic of the AFM applies whe n multielement stimuli contain relevant and irrelevant elements. Targe t Size (TS) and symbolic S-R Compatibility (SRC) were manipulated in t hree reaction time (RT) experiments. TS and SRC are assumed in the AFM literature to selectively influence the independent stages of feature extraction and S-R translation, respectively. Experiment 1 showed tha t the effects of TS and SRC on RT were additive when the target was pr esented in isolation and this additive relation was not changed when t he target was flanked by stimuli that contained no information relevan t to the response. In Experiment 2, this additivity changed into a sup eradditive interaction when flankers signaled the same response as the target: The effect of SRC was larger when targets were small rather t han large. The overall pattern of findings violated the AFM stage robu stness criterion. Neither a discrete stage model nor a continuous flow conception account for the results. To explain flanker effects on tar get processing a dual-process architecture was formulated that assumes that perceptual information is processed along concurrently engaged r outes: An attentive processing route and a direct priming route. Exper iment 3 confirmed the prediction of the dual-process model that the re lation between TS and SRC would be subadditive when flankers signal th e response opposite to that designated by the target.