Dichotic and bisensory grouping effects

The relationship between the Gray and Wedderburn effect, the channel alternation effect and the class alternation effect was studied in dichotic and bisensory experiments using physically and semantically distinguishable word classes. With dichotic presentation all three effects were found to occur, but with bisensory presentation neither the Gray and Wedderburn effect nor the class alternation effect was detected. There were no significant differences between physically and semantically based grouping. The present investigation provides support for Broadbent's claim that the Gray and Wedderburn effect depends on the occurrence of the class alternation effect. The various dichotic and bisensory grouping effects are explicable in terms of selection by modality-specific processing systems.