Atas, A., Faivre, N., Timmermans, B., Cleeremans, A., & Kouider, S. (in press). Nonconscious learning from crowded sequences. Psychological Science.
Can people learn complex information without conscious awareness? Implicit learning—learning without awareness of what has been learned—has been the focus of intense investigation over the last 50 years. However, it remains controversial whether complex knowledge can be learned implicitly. In the research reported here, we addressed this challenge by asking participants to differentiate between sequences of symbols they could not perceive consciously. Using an operant-conditioning task, we showed that participants learned to associate distinct sequences of crowded (nondiscriminable) symbols with their respective monetary outcomes (reward or punishment). Overall, our study demonstrates that sensitivity to sequential regularities can arise through the nonconscious temporal integration of perceptual information.
Atas, A., Vermeiren, A., & Cleeremans, A. (2013). Repeating a strongly masked stimulus increases priming and awareness. Consciousness and Cognition, 22, 1422-1430.
Previous studies [Marcel, A. J. (1983). Conscious and unconscious perception: Experiments on visual masking and word recognition. Cognitive Psychology, 15(2), 197–237; Wentura, D., & Frings, C. (2005). Repeated masked category primes interfere with related exemplars: New evidence for negative semantic priming. Journal of Experimental Psychology: Learning, Memory, and Cognition, 31(1), 108–120] suggested that repeatedly presenting a masked stimulus improves priming without increasing perceptual awareness. However, neural the- ories of consciousness predict the opposite: Increasing bottom-up strength in such a par- adigm should also result in increasing availability to awareness. Here, we tested this prediction by manipulating the number of repetitions of a strongly masked digit. Our results do not replicate the dissociation observed in previous studies and are instead sug- gestive that repeating an unconscious and attended masked stimulus enables the progres- sive emergence of perceptual awareness.
￼Windey, B., Vermeiren, A., Atas, A., & Cleeremans, A. (2014). The graded and dichotomous nature of visual awareness. Philosophical Transactions of the Royal Society B, 369: 20130282
Is our visual experience of the world graded or dichotomous? Opposite pre- theoretical intuitions apply in different cases. For instance, when looking at a scene, one has a distinct sense that our experience has a graded character: one cannot say that there is no experience of contents that fall outside the focus of attention, but one cannot say that there is full awareness of such contents either. By contrast, when performing a visual detection task, our sense of having perceived the stimulus or not exhibits a more dichoto- mous character. Such issues have recently been the object of intense debate because different theoretical frameworks make different predictions about the graded versus dichotomous character of consciousness. Here, we review both relevant empirical findings as well as the associated theories (i.e. local recurrent processing versus global neural workspace theory). Next, we attempt to reconcile such contradictory theories by suggesting that level of processing is an often-ignored but highly relevant dimension through which we can cast a novel look at existing empirical findings. Thus, using a range of different stimuli, tasks and subjective scales, we show that proces- sing low-level, non-semantic content results in graded visual experience, whereas processing high-level semantic content is experienced in a more dichotomous manner. We close by comparing our perspective with existing proposals, focusing in particular on the partial awareness hypothesis.