The repetition discrimination task: an objective method for studying perceptual grouping.

Five experiments are reported that demonstrate the use of the repetition discrimination task (RDT) to study perceptual grouping effects objectively and quantitatively. Experiments 1 and 3 validate the method by measuring grouping based on proximity, color similarity, common region, and element connectedness. Experiment 2 compares the RDT effects for proximity grouping to explicit subjective ratings of grouping strength in identical displays. Experiments 4 and 5 investigate the effects of size and orientation of surrounding ovals in displays in which competing organizations are present. In each case, the RDT produces clear, consistent patterns of response times that are consistent with predictions based on grouping. It thus represents an objective method for studying the full range of grouping phenomena originally described by Wertheimer.