Unconscious associative learning with conscious cues

Despite extensive research, the very existence of unconscious learning in humans remains much debated. Skepticism arises chiefly from the difficulty in assessing the level of awareness of the complex associations learned in classical implicit learning paradigms. Here, we show that simple associations between colors and motion directions can be learned unconsciously. In each trial, participants had to report the motion direction of a patch of colored dots but unbeknownst to the participants, two out of the three possible colors were always associated with a given direction/response, while one was uninformative. We confirm the lack of awareness by using several tasks, fulfilling the most stringent criteria. In addition, we show the crucial role of trial-by-trial feedback, and that both the stimulus-response (motor) and stimulus-stimulus (perceptual) associations were learned. In conclusion, we demonstrate that simple associations between supraliminal stimulus features can be learned unconsciously, providing a novel framework to study unconscious learning.