Effects of three diagram instruction methods on transfer of diagram comprehension skills: The critical role of inference while learning

Can students be taught to better comprehend the diagrams in their textbooks? Can such teaching transfer to uninstructed diagrams in the same domain or even in a new domain? What methods work best for these goals? Building on previous research showing positive results compared to control groups in both laboratory studies and short-term interventions, the authors developed three 6-week-long classroom treatments and compared their effectiveness in a sample of 137 high school biology students. Treatments involved students generating explanations (Self-Expl), completing a diagram with graphic elements (SCD-Visual), or completing a diagram with text (SCD-Verbal). Treatments were both effective for literal and inferential biology diagram comprehension, but the Self-Expl treatment showed greater pre-posttest gains on inferential items and SCD-Visual showed greater gains on literal items. Far transfer to geoscience diagram comprehension was only found for SCD-Verbal. There were no gains on biology knowledge for SCD-Visual. Analyses of instructional materials and students' coded answers during the intervention suggest that Self-Expl and SCD-Verbal conditions fostered more effort and more inferences while learning than did SCD-Visual. Results are consistent with the emphasis on inference in Hegarty's model of diagram comprehension.