When problem solving is superior to studying worked examples.

Interactions between levels of learner knowledge in a domain and levels of instructional guidance were investigated. Inexperienced mechanical trade apprentices were presented with either a series of worked examples to study or problems to solve. On subsequent tests, inexperienced trainees benefited most from the worked examples condition, with this group performing better with lower ratings of mental load than similar trainees who solved problems. With more experience in the domain, worked examples became redundant and problem solving proved superior. It is suggested that the relative effectiveness of either worked examples or problem solving depends heavily on levels of learner knowledge.