Is consciousness a gradual phenomenon? Evidence for an all-or-none bifurcation during the attentional blink.
Several theories of the neural correlates of consciousness assume that there is a continuum of perception, associated with a gradual change in the intensity of brain activation. But some models, considering reverberation of neural activity as necessary for conscious perception, predict a sharp nonlinear transition between unconscious and conscious processing. We asked participants to evaluate the visibility of target words on a continuous scale during the attentional blink, which is known to impede explicit reports. Participants used this continuous scale in an all-or-none fashion: Targets presented during the blink were either identified as well as targets presented outside the blink period or not detected at all. We suggest that a stochastic nonlinear bifurcation in neural activity underlies the all-or-none perception observed during the attentional blink.
Sergent
Claire
C
Institut National de la Santé et de la Recherche Médicale Unité 562, Service Hospitalier Frédéric Joliot, Commissariat à l'Energie Atomique, Orsay, France. sergent@shfj.cea.fr
Dehaene
Stanislas
S
D000328:Adult; D003243:Consciousness / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D014793:Visual Cortex / Q000502:physiology; D014796:Visual Perception