Externalization vs. internalization: The influence on problem solving performance

This research investigates how externalizing information in program-interfaces influences problem solving performance. Externalization as screen-representation provides relevant interface-feedback, and remembering certain task-related knowledge becomes unnecessary, relieving working memory (WM). Examples are visual feedback aids such as "graying out" non-applicable menu-items. Differently, when certain task-related information is unavailable, it needs to be internalized, stored in WM. We examined the hypotheses that externalization yields better performance during initial learning, while later, internalization yields better performance and knowledge. Two versions (internalized & externalized) of an isomorph of the "missionaries and cannibals" problem were tested 30 subjects solved 6 problems, then performed a distraction task erasing WM, and solved 3 more problems. Also knowledge of the problem's rules and states was tested. Internalization yielded better knowledge and reaching less dead-end problem-states. Time needed, steps and error-rates were in the expected direction, but not significantly. This research contributes to GUI design-guidelines for human-computer interaction of problem-solving tasks.