Does Consciousness Disappear in Dreamless Sleep?

The assumption that consciousness disappears during deep, dreamless sleep is oversimplified. Empirical and theoretical reasons indicate that a range of different types of sleep experience, some distinct from dreaming, can occur in all sleep stages. A novel taxonomy for describing these dreamless sleep experiences is introduced, along with research methods for their investigation. Future studies should focus on memory consolidation, sleep disorders, and sleep state (mis)perception. This proposal suggests new directions for sleep and dream science, the neuroscience of consciousness, and can inform the diagnosis and treatment of sleep disorders.

Study at a glance

Abstract

Consciousness is often said to disappear in deep, dreamless sleep. We argue that this assumption is oversimplified. Unless dreamless sleep is defined as unconscious from the outset there are good empirical and theoretical reasons for saying that a range of different types of sleep experience, some of which are distinct from dreaming, can occur in all stages of sleep. We introduce a novel taxonomy for describing different kinds of dreamless sleep experiences and suggest research methods for their investigation. Future studies should focus on three areas: memory consolidation, sleep disorders, and sleep state (mis)perception. Our proposal suggests new directions for sleep and dream science, as well as for the neuroscience of consciousness, and can also inform the diagnosis and treatment of sleep disorders.