Some experiences linger in mind, spontaneously returning to our thoughts for minutes after their conclusion. Other experiences fall out of mind immediately. It remains unclear why. We hypothesize that an input is more likely to persist in our thoughts when it has been deeply processed: when we have extracted its situational meaning rather than its physical properties or low-level semantics. Here, participants read sequences of words with different levels of coherence (word-, sentence-, or narrative-level). We probe participants’ spontaneous thoughts via free word association, before and after reading. By measuring lingering subjectively (via self-report) and objectively (via changes in free association content), we find that information lingers when it is coherent at the narrative level. Furthermore, and an individual’s feeling of transportation into reading material predicts lingering better than the material’s objective coherence. Thus, our thoughts in the present moment echo prior experiences that have been incorporated into deeper, narrative forms of thinking.

Our mental experience is largely continuous on the scale of seconds and minutes. However, this continuity does not always arise from a volitional carrying forward of ideas. Instead, recent actions, thoughts, dispositions, and emotions can persist in mind, continually shaping our later experience. Aspects of this fundamental property of human cognition— psychological momentum—have been studied under the rubrics of mindset, mood, memory, task set, and mind wandering. Reviewing these largely independent threads of research, we argue that psychological momentum needs to be understood from an integrated perspective as an adaptation that, although sometimes costly, carries forward thoughts and dispositions that respond to the current and future environment.

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