When do we become conscious of a stimulus after its presentation? We would all agree that this necessarily takes time and that it is not instantaneous. Here, I would like to propose not only that conscious access is
delayed
relative to the external stimulation, but also that it can flexibly
desynchronize
from external stimulation; it can process some information ‘offline’, if and when it becomes relevant. Thus, in contrast with initial sensory processing, conscious experience might not strictly follow the sequence of events in the environment. In this article, I will review gathering evidence in favour of this proposition. I will argue that it offers a coherent framework for explaining a great variety of observations in the domain of perception, sensory memory and working memory: the psychological refractory period, the attentional blink, post-dictive phenomena, iconic memory, latent working memory and the newly described retro-perception phenomenon. I will integrate this proposition to the global neuronal workspace model and consider possible underlying brain mechanisms. Finally, I will argue that this capacity to process information ‘offline’ might have made conscious processing evolutionarily advantageous in spite of its sluggishness and capacity limitations.
This article is part of the theme issue ‘Perceptual consciousness and cognitive access’.
Signatures of conscious processing in the human brain