Interpolated testing and content pretesting as interventions to reduce task-unrelated thoughts during a video lecture.

Considerable research has examined the prevalence and apparent consequences of task-unrelated thoughts (TUTs) in both laboratory and authentic educational settings. Few studies, however, have explored methods to reduce TUTs during learning; those few studies tested small samples or used unvalidated TUT assessments. The present experimental study attempted to conceptually replicate or extend previous findings of interpolated testing and pretesting effects on TUT and learning. In a study of 195 U.S. undergraduates, we investigated whether interpolated testing (compared to interpolated restudy) and pretesting on lecture-relevant materials (compared to pretesting on conceptually related but lecture-irrelevant materials) would reduce TUTs during a video lecture on introductory statistics. Subjects completed either a content-matched or content-mismatched pretest on statistics concepts and then watched a narrated lecture slideshow. During the lecture, half of the sample completed interpolated tests on the lecture material and half completed interpolated restudy of that material. All subjects responded to unpredictably presented thought probes during the video to assess their immediately preceding thoughts, including TUTs. Following the lecture, students reported on their situational interest elicited by the lecture and then completed a posttest. Interpolated testing significantly reduced TUT rates during the lecture compared to restudying, conceptually replicating previous findings-but with a small effect size and no supporting Bayes-factor evidence. We found statistical evidence for neither an interpolated testing effect on learning, nor an effect of matched-content pretesting on TUT rates or learning. Interpolated testing might have limited utility to support students' attention, but varying effect sizes across studies warrants further work.