Abstract

To investigate unconscious processing, researchers often present sequences of different stimuli (mask, prime, target) and compare two tasks: In the direct task, participants directly respond to a masked prime. In the indirect task, participants respond to a target preceded by the masked prime. Typically, the prime has effects on reaction times in the indirect task, which is interpreted as preserved unconscious processing of the prime. However, this paradigm is problematic, because participants are restricted to a binary response in the direct task. 12 participants gave a binary response and also judged their confidence on a continuous scale. We found that confidence modulated the accuracy of prime detection: Overall accuracy (mean+/-SEM in percent): 58.6+/-1.4; accuracy in high/low- confidence trials: 64.4+/-2.1 / 53.5+/-1.1. We also applied classic information theory and found that the higher accuracies in high/low confidence trials increased the overall information about the prime.