Is Consciousness a Gradual Phenomenon?

TLDR

Theories of neural correlates of consciousness posit a continuum of perception linked to gradual brain activation, yet some models predict a sharp nonlinear transition between unconscious and conscious processing. The study proposes that a stochastic nonlinear bifurcation in neural activity underlies the all‑or‑none perception observed during the attentional blink. Participants evaluated target word visibility on a continuous scale during the attentional blink, a paradigm that impedes explicit reports. Participants reported an all‑or‑none pattern, with targets during the blink either identified as well as those outside the blink or not detected at all.

Abstract

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.