Perception below the Objective Threshold?

Abstract The experiments reported by Snodgrass, Shevrin, and Kopka (1993) appear to demonstrate that words are perceived even when overall forced-choice discrimination performance does not deviate from chance. We replicated their critical finding in two separate experiments; our results indicated that the subjects′ preferences for one of the two strategy conditions (i.e., pop or look) predicted significant deviations from chance performance in the pop condition, even though the overall performance in this condition did not differ from chance. In addition, we found that task preference had no effect when blank cards rather than words were presented and that the words could not be detected when subjects were simply asked to decide on each trial whether a stimulus had been presented. These results suggest that it is possible to demonstrate perception below an objective threshold defined in terms of overall discrimination performance. As such, the results highlight the importance of considering individual differences in studies of perception without awareness.