Are we really unconscious in “unconscious” states? Common assumptions revisited

Consciousness research frequently relies on the assumption that subjects in deep sleep or under general anesthesia are unconscious, using these states as “off” conditions against which to contrast wakefulness. This perspective article critically examines that assumption.

The authors identify three compounding problems: (1) behavioral unresponsiveness is an unreliable proxy for absence of experience—patients under anesthesia and sleepers in slow-wave sleep regularly report experiences when probed with sensitive paradigms; (2) reliance on post-awakening verbal report introduces memory confounds, since the failure to recall an experience does not imply it did not occur; and (3) even when experiences are reported, their contents are rarely assessed in detail, potentially masking rich inner states.

Empirical data are reviewed showing that 20–70% of awakenings from stages previously considered “unconscious” yield dream-like reports. In response, the authors propose three complementary approaches: pragmatic state characterization by operational criteria; descriptive mapping of specific phenomenological and neural properties; and predictive decoding using neural data to infer subjective state without relying solely on behavioral report. The paper calls for precision in the use of “unconscious” and greater attention to the experiences that may persist across traditionally defined states of reduced consciousness.

Recommended citation: Sevenius Nilsen A, Juel BE, Thürer B, Aamodt A, Storm JF. (2022). "Are we really unconscious in 'unconscious' states? Common assumptions revisited." Frontiers in Human Neuroscience. 16:987051. https://doi.org/10.3389/fnhum.2022.987051
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