This study investigated learners' preconceptions of interactive video (IV), instructional television (ITV), and television (TV), and compared three treatment groups on learners' perceptions of invested mental effort and achievement on a test of recall and inference. The three treatments consisted of an IV lesson that included practice questions requiring an active response, an ITV lesson that included practice questions requiring a covert response, and a TV lesson that did not include practice questions. The relationship between learners' preconceptions and perceived mental effort was also investigated. The subjects were 78 undergraduate students who were randomly selected and assigned to the three treatments, and a posttest only control group design was used. The independent variable consisted of the video-based instructional materials, and the dependent variables were student ratings of perceived mental effort, recall scores, and inference scores. Information on student preconceptions of the difficulty of learning from IV, ITV, and TV was also collected for descriptive and correlational purposes. Several statistical tests of significance were used to analyze the data, including analysis of variance (ANOVA), Tukey's Honestly Significant Difference (HSD) test, and Pearson's test of correlation. The results of the study indicate that learners who are required to actively respond to practice questions that are embedded in a video-based lesson recall significantly more information from the lesson than learners who are not provided with practice questions. It is suggested that, although the inclusion of such questions does increase the amount of factual information recalled, higher level practice questions may be needed to increase the number of inferences generated in response to a video-based lesson. (21 references) (BBM)