Perception without awareness

Abstract

Two experiments were carried out in order to re-examine the phenomenon of subliminal perception, c.q. perception without awareness. Subliminal perception, c.q. perception without awareness, was defined in terms of the subjects' ability to respond differentially to the content of stimuli like words or digits, without having consciously identified their meaning.

In the first experiment, subliminal visual perception was examined in terms of the subjects' ability to respond differentially to Dutch stimulus words of positive versus negative emotional connotation, which were presented at such a low level of light intensity that the subjects were unable to perceive even their presence at the conscious level. The critical measures of the ability to respond differentially were the associative reaction times.

In the secon experiment, which was disguised as being related to extrasensory perception, the number ‘5’ served as the visual stimulus and was presented at such a marginal level of intensity that some of the subjects would consciously perceive it, while the others did not. However, all the subjects, also those of the latter category, were able to perceive and identify his stimulus when their attention was explicitly called to it. The question was, whether those subjects who did not perceive this marginal supraliminal stimulus at the conscious level, would nevertheless be affected by it in the predicted direction, or not.

Perception without awareness could not be demonstrated at either of these two intensities of stimulation. An attempt was made to explain the differences in results between these experiments and those which allegedly have demonstrated the phenomenon of visual perception without awareness.