Exploring the effects of physics explainer videos and written explanations on declarative knowledge and the illusion of understanding

Studies have shown the potential of science explainer videos. An alternative is a written explanation, as found in science textbooks. Prior research suggests that instructional explanations sometimes lead to the belief that a topic has been fully understood, even though that is, objectively, not the case. This “illusion of understanding” may be affected by the medium of the explanation. Animations tend to falsely imply an easy explanation, which might result in explainer videos supporting the illusion of understanding. Textbook entries may appear to be more reliable and formal, resulting in an overestimation of the learning gains from this medium. Also, prior studies comparing the achievement from both media come to ambiguous results. In the present experimental study (N = 150 learners), we compared the effects of an explainer video introducing the concept of force to a written explanation containing the script of the video and two images, as though it is a page from a textbook. Both groups achieved comparable degrees of declarative knowledge, however, the written explanation video group had a significantly higher belief of understanding (partial 𝜼2 = 0.043) that did not correspond with their actual learning progress. Consequences of this potential illusion of understanding may include lower cognitive activation and less motivation in science classrooms if learning environments exclude further learning tasks that allow for a more realistic picture of understanding. That might suggest that it is sometimes potentially harmful to leave physics learners to their own devices with instructional material.