Unconscious semantic priming from pictures under backward masking and continuous flash suppression

It is debated which perceptual functions can take place unconsciously and which depend on conscious awareness. Here, we tested whether the meaning of invisible pictures can be processed unconsciously, and whether this would depend on the psychophysical technique used to render these images invisible. We measured whether pictures of animals or objects presented under backward masking or continuous flash suppression could prime the subsequent categorization of target words into animal or non-animal. The backward masking experiment failed to replicate the priming effect reported in two previous studies, despite sufficient statistical power. Similarly, the continuous flash suppression experiment provided no evidence for a priming effect. Thus, our experiments failed to demonstrate unconscious semantic processing of pictures. These results support the emerging view that unconscious processing is rather limited in scope.