The cognitive load and learning effects of dual-code and interactivity--two multimedia methods intended to promote meaningful learning--were examined. In Experiment 1, college students learned about the causal chain of events leading to the process of lightning formation with a set of words and corresponding pictures (Group WP), pictures (Group P), or words (Group W). Some students were presented with the organized causal chain of events to study, whereas others were given a self-organization task. Consistent with a cognitive theory of multimedia learning, Condition WP was the highest in instructional efficiency for retention and transfer. However, contrary to our predictions, having students organize the multimedia materials was detrimental to transfer. Two follow-up experiments tested the hypotheses that the negative effects of interactivity were due to students' lack of time control (Experiment 2) and the form of feedback (Experiment 3). The findings showed that interactivity was effective when students were asked to evaluate their answers before receiving corrective feedback from the system.