Perception without awareness in a dichoptic viewing situation

One way of investigating perception without awareness is to utilize the phenomenon of binocular rivalry. The dichoptic viewing situation can be so arranged that a stimulus may be above identification level (when presented alone) but masked by contiguous stimulation, i.e. a brighter image to the other eye. This experimental situation was used to replicate an experiment of Smith et al. (1959) which claimed to demonstrate that differences in meaning between words registered below recognition threshold could affect associated conscious thoughts. In the two experiments reported here, a neutral face was paired with affect words presented subliminally and subjects were asked to rate its expression using a forced-choice indicator. Additional controls to those of Smith et al. were used. In Expt. I it was established that words presented outside of awareness had an effect on semantically related judgements, which was at least as great as that with the same words presented supraliminally. In Expt. II this was confirmed and it was found that increasing the similarity of contour between critical and control words of different meaning suggested differences between subliminal and supraliminal sessions. Responses tended to be meaning-related in the former and structure-related in the latter. It was suggested that the experiments have relevance to current theories of selective attention.