The efficacy of gating in the processing of simple, multidimensional stimuli was investigated. In Experiment 1, a continuous classification task was used, with subjects sorting cards according to binary dimensions of line orientation and location. Results suggested that orientation and location are integral dimensions, facilitation occurring with correlated dimensional combinations and interference with orthogonal combinations. In Experiment 2, discrete reaction time (RT) trials were given, requiring classification of tachistoscopically presented stimuli with large Response-Stimulus intervals (l3 sec). Interference, but not facilitation was found. Analysis of sequential effects revealed no support for the hypothesis that interference is due to the greater frequency of stimulus change in orthogonal conditions. It is suggested that long RSIs induce a set to process stimuli beyond psychological similarity and to analyze the dimensional structure of integral dimensions. Such dimensional analysis would eliminate facilitation effects, and interference might be due to response competition. (Author)