Overprompting students by providing them with strong hints to answers of questions can do learners more instructional harm than good. The selective attention model was used to explain the effects of overprompting students provided with study questions adjunct to a complex flow diagram describing scientific cyclical schema. Tenth-grade students were randomly assigned to an unprompted-question, no-question, prompted-question, and a placebo control group. Analysis showed that strongly prompting students to the answers of such questions was less effective than an unprompted question treatment, p < 0.05. The no-question treatment did not significantly outperform the prompted treatment. The information presented in the flow diagram was operationally related to comprehension study and posttest questions. The theoretical discussion and the present findings suggested that science teachers should use prompting techniques with extreme caution.