Should a Teaching Article Explain Why It Matters or Add Fun Facts? Experiments on Stating Usefulness, Writing About Usefulness, Choice, and Irrelevant Details
Telling readers what something is good for makes them rate the material as more useful, but across seven experiments no difference was detected in immediate test scores; in classroom studies where students wrote about usefulness themselves, results flipped across students and courses. Interesting details unrelated to the main point lowered immediate test scores on average, by an uncertain amount; only one pair of experiments detected no harm when learning was voluntary.