In self-paced learning, when the regulation of effort is goal driven (e.g., allocated to different items according to their relative importance), judgments of learning (JOLs) increase with study time. When it is data driven (i.e., determined by the ease of committing the item to memory), JOLs decrease with study time (Koriat, Ma'ayan, & Nussinson, 2006). Because the amount of effort invested in different items is conjointly determined by data-driven and goal-driven regulation, an attribution process must be postulated in which variations in effort are attributed by the learner to data-driven or goal-driven regulation before the implications for metacognitive judgments are determined. To support the reality of this process, the authors asked learners to adopt a facial expression that creates a feeling of effort and induced them to attribute that effort either to data-driven or to goal-driven regulation. This manipulation was found to determine the direction in which experienced effort affected metacognitive judgment. (Contains 1 table, 1 figure, and 1 footnote.)