When Perception Trumps Reality

Is semantic priming driven by the objective or perceived meaning of the priming stimulus? This question is relevant given that many studies suggest that the objective meaning of invisible stimuli can influence cognitive processes and behavior. In an experiment involving 66 participants, we tested how the perceived meaning of misperceived stimuli influenced response times. Stroop priming (i.e., longer response times for incongruent than for congruent prime-target pairs) was observed in trials in which the prime was correctly identified. However, reversed Stroop priming was observed when the prime stimulus was incorrectly identified. Even in trials in which participants reported no perception of the prime and identified the primes at close to chance level (i.e., trials that meet both subjective and objective definitions of being subliminal), Stroop priming corresponded to perceived congruency, not objective congruency. This result suggests that occasional weak percepts and mispercepts are intermixed with no percepts in conditions traditionally claimed to be subliminal, casting doubt on claims of subliminal priming made in previous reports.