The Temporal Interplay between Conscious and Unconscious Perceptual Streams

• Published in: Current biology Vol. 19; no. 23; pp. 2003 - 2007
• Main Authors: Wu, Chien-Te, Busch, Niko A., Fabre-Thorpe, Michèle, VanRullen, Rufin
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 15.12.2009; Elsevier
• Subjects: Humans; Life Sciences; Motion Perception; Neurons and Cognition; Photic Stimulation; SYSNEURO; Time Factors; Unconscious (Psychology); Visual Perception - physiology; SYSNEURO
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2009.10.017

An optimal correspondence of temporal information between the physical world and our perceptual world is important for survival. In the current study, we demonstrate a novel temporal illusion in which the cause of a perceptual event is perceived after the event itself. We used a paradigm referred to as motion-induced blindness (MIB), in which a static visual target presented on a constantly rotating background disappears and reappears from awareness periodically [1–3], with the dynamic characteristics of bistable perception [4]. A sudden stimulus onset (e.g., a flash) presented during a period of perceptual suppression (i.e., during MIB) is known to trigger the almost instantaneous reappearance of the suppressed target [5]. Surprisingly, however, we report here that although the sudden flash is the cause of the static target's reappearance (the corresponding effect), it is systematically perceived as occurring after this reappearance. Further investigation revealed that this illusory temporal reversal is caused by an ∼100 ms advantage for the unconscious representation of the perceptually suppressed target to access consciousness, as compared to the newly presented flash. This new temporal illusion therefore reveals the normally hidden delays in bringing new visual events to awareness.