Relating mind-blanking to the content and dynamics of spontaneous thinking

During wakefulness, the stream of thought is occasionally interrupted by moments when we cannot report any content, termed ‘mind-blanking’ (MB). As MB is a relatively unexplored mental state, we here examine how it relates to spontaneous thinking, namely, thought content and thought dynamics. By reviewing empirical studies on the neural correlates of MB, we first indicate that MB reports are mediated by variations in cortical and physiological arousal levels. In terms of thought content, we propose to view MB on a dimensional space representing content types, where MB is unrelated to any type of content. In terms of thought dynamics, we suggest conceptualizing MB as a moment during content transitioning or as a failure to transition across contents. Taken together, we suggest that MB has a unique place in the study of spontaneous thinking, and its inclusion can facilitate the isolation of the neural correlates of ongoing cognition.