Mechanisms underlying disfluency effects: a systematic review, Механизмы эффекта не-беглости: систематический обзор

<jats:p>Introduction. Although some studies link disfluency – the subjective experience of difficulty in processing information – to cognitive and metacognitive benefits, empirical findings remain inconsistent, often showing null or negative effects, while theoretical explanations remain fragmented. Objective. The aim of this review was to systematize and clarify the mechanisms through which disfluency influences cognitive, metacognitive, and behavioral outcomes. Methods. A systematic review of 110 empirical studies was conducted. Results. Five key mechanisms were identified: (1) disfluency as a metacognitive cue, (2) disfluency as a signal of cognitive engagement, (3) processing-based changes, such as compensatory processing, (4) affective and hedonic marking, and (5) moderation by naïve theories. The most robust effect concerns metacognitive illusions: disfluency lowers judgments of learning without affecting actual memory performance. Cognitive benefits emerge only under specific conditions, such as high working memory capacity or motivation, whereas many high-quality studies report no disfluency effects at all. Conclusions. The field needs to move toward mechanism-specific research. To support this direction, the review presents a library of manipulations and control conditions, as well as recommendations for empirically testing precise theoretical predictions.</jats:p>