Perceptual fluency affects judgments of learning: The font size effect

The font size effect on judgments of learning (JOLs) refers to the fact that people give higher JOLs to large than to small font size words, despite font size having no effect on retention. The effect is important because it spotlights a process dissociation between metacognitive judgments about memory and memory performance itself. Previous research has proposed a fluency theory to account for this effect, but this theory has been contradicted by a recent study which found no difference in response times (RTs) - and hence fluency - in a lexical decision task between large and small words (Mueller, Dunlosky, Tauber, & Rhodes, 2014). In the current research, we further tested the fluency theory by employing a continuous identification (CID) task in Experiment 1 and by explicitly comparing the CID and lexical decision tasks in Experiment 2. We show that lexical decision is an inappropriate instrument for measuring differences in perceptual fluency. The CID task, in contrast, provides direct evidence that the stimulus size effect on JOLs is substantially mediated by perceptual fluency. Experiment 3 found that fluency is at least as important as beliefs about font size in contributing to the font size effect on JOLs.