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Comparing the phenomenological qualities of stimulus-independent thought, stimulus-dependent thought and dreams using experience sampling

Madeleine E. Gross, Anna Smith, Yvette M. Graveline, Roger E. Beaty, Jonathan W. Schooler, Paul Seli

Philosophical Transactions of the Royal Society B Biological Sciences December 13, 2020 DOI: 10.1098/rstb.2019.0694 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Experience-sampling study Qualitative Peer reviewed
Duration 7-day
Keywords Stimulus psychology Optimal distinctiveness theory Cognitive psychology Perception Mind-wandering Phenomenology philosophy Cognition Epistemology
Citations 37
Key points Dreaming, waking stimulus-independent thoughts, and stimulus-dependent thoughts are substantially distinct, with significant differences between at least two of the three across all measured variables.

Abstract

Humans spend a considerable portion of their lives engaged in 'stimulus-independent thoughts' (SIT), or mental activity that occurs independently of input from the immediate external environment. Although such SITs are, by definition, different from thoughts that are driven by stimuli in one's external environment (i.e. stimulus-dependent thoughts; SDTs), at times, the phenomenology of these two types of thought appears to be deceptively similar. But how similar are they? We address this question by comparing the content of two types of SIT (dreaming and waking SITs) with the content of SDTs. In this 7 day, smartphone-based experience-sampling procedure, participants were intermittently probed during the day and night to indicate whether their current thoughts were stimulus dependent or stimulus independent. They then responded to content-based items indexing the qualitative aspects of their experience (e.g. My thoughts were jumping from topic to topic). Results indicate substantial distinctiveness between these three types of thought: significant differences between at least two of the three mental states were found across every measured variable. Implications are discussed. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.