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.