Inferring the direction of implied motion depends on visual awareness.
Visual awareness of an event, object, or scene is, by essence, an integrated experience, whereby different visual features composing an object (e.g., orientation, color, shape) appear as an unified percept and are processed as a whole. Here, we tested in human observers whether perceptual integration of static motion cues depends on awareness by measuring the capacity to infer the direction of motion implied by a static visible or invisible image under continuous flash suppression. Using measures of directional adaptation, we found that visible but not invisible implied motion adaptors biased the perception of real motion probes. In a control experiment, we found that invisible adaptors implying motion primed the perception of subsequent probes when they were identical (i.e., repetition priming), but not when they only shared the same direction (i.e., direction priming). Furthermore, using a model of visual processing, we argue that repetition priming effects are likely to arise as early as in the primary visual cortex. We conclude that although invisible images implying motion undergo some form of nonconscious processing, visual awareness is necessary to make inferences about motion direction.
Computation and Neural Systems, California Institute of Technology, Pasadena, CA, USA.
Nathan
N
Faivre
Christof
C
Koch
D000221:Adaptation, Ocular / Q000502:physiology; D000293:Adolescent; D000328:Adult; D001364:Awareness / Q000502:physiology*; D003463:Cues; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D009949:Orientation / Q000502:physiology*; D055815:Young Adult
awareness; consciousness; continuous flash suppression; implied motion; priming