An Illusion Analysis on the Judgment of Effectiveness and Use of Learning Strategies Based on Sequential Bayesian Inference

This study investigates the illusion of effectiveness in students’ use of learning strategies using sequential Bayesian inference. Undergraduate students in a liberal arts course were surveyed about the perceived effectiveness and intended use of two strategies—retrieval practice and highlighting/underlining—under two test scenarios: one scheduled in two days and another in three months. The study calculated the conditional probability of using a strategy judged effective, aiming to detect illusions. Posterior probabilities from a prior study were used as priors in a typical sequential Bayesian framework. New data from 67 students were used to update these priors and generate revised posteriors. Two research questions were addressed. The first compared strategy use under 50:50 and 70:30 prior assumptions, reflecting either ignorance or prior findings. The second applied previous posteriors directly as priors to confirm the presence of illusions. Findings revealed consistent illusions. Highlighting/ underlining was underused when it should have been emphasized, while retrieval practice was misapplied in both directions. These mismatches were stronger for retrieval practice in the second analysis. Overall, students showed limited awareness of when to use each strategy and often failed to act according to their own judgments of effectiveness. Sequential Bayesian inference proved effective in quantifying and validating these cognitive biases in learning behavior.