Deciphering temporal scales of visual awareness: insights from flicker frequency modulation in continuous flash suppression.

Evidence from temporal regularities in perception, temporal phenomenology, and neural dynamics indicate that our awareness evolves and devolves over several timescales. However, most theories of consciousness posit a single timescale of processing at the end of which a percept is rendered conscious. To show evidence for multiple timescales, we utilized continuous flash suppression (CFS). Based on a hierarchical framework of temporal phenomenology, we reasoned that different flicker rates (1, 4, 10, and 25 Hz) of the suppressor should be able to perturb phenomenologically distinct tasks. We designed four experiments that used different perceptual tasks (N = 48). The results showed that entry of contents into conscious awareness, their attentional sampling, perceptual grouping, and exiting from awareness were all maximally perturbed at distinct flicker frequencies of the suppressor in a CFS paradigm. Our demonstration shows that different flicker frequencies perturb different phenomenological aspects of awareness, and these flicker frequencies systematically map onto temporal hierarchies of timing of awareness.