Scott, R. & Dienes, Z.
University of Sussex, Brighton, UK
Implicit learning paradigms reliably demonstrate associative learning without conscious awareness of the association being learnt. However, while the relationship between stimuli may be unconscious the stimuli themselves are consciously perceived. We examine if associative learning can be achieved without conscious perception. Face stimuli are employed to capitalise on the large cortical resource dedicated to face processing. Repeated back masking is used to extend unconscious exposure to approximately 2 seconds. Participants’ subjective perceptual thresholds were identified using sample images. Whole face pairs or scrambled face pairs were presented and back masked with a random block pattern. Participants indicated whether the faces were whole or scrambled and rated their confidence. Exposure duration was progressively reduced until zero confidence was reported on ten consecutive trials. Training involved sub-threshold exposure to a randomly selected 20 of 30 face pairs. Exposure consisted of two sets of 20 repeats of the image presented below the identified threshold and masked with a random pattern. Each pair included one male and one female face. Participants reported if the male face was on the left or the right and indicated their confidence. If confidence was above zero the exposure duration was further reduced and the given face pair excluded from the test phase. At test participants rated the correctness of 30 pairs of faces: 10 unchanged from training, 10 with the position of the faces swapped, and 10 new pairs. Judgments regarding the location of the male face during training were at chance (M=.51, SE=.02, t(17)=.31, p=.760, CI95% .47:.55). Nonetheless, the correctness ratings given to swapped face pairs (M=1.76, SE=.10) were significantly lower than those for unchanged pairs (M=1.99, SE=.11, t(20)=3.04, p=.006). Sensitivity to the change in configuration of stimuli only previously seen subliminally provides evidence that associative learning can be achieved both unconsciously and without conscious perception.