Can more help be worse?
Christof van Nimwegen, Herre van Oostendorp, Hermina Schijf · 2004
The premise of this research is that assistance can make interactions easier, but does not necessarily aid understanding. A way to assist users is displaying relevant information in interfaces. Recall of such knowledge is unnecessary and working memory is relieved. Examples are visual aids such as the of items, which can become unclickable indicating that an action is not possible. If this is not done this information has to be inferred by the user himself. An experiment was conducted in which subjects had to solve a series of puzzles. We hypothesized that providing greyed-out items (externalization) yields better performance during initial learning. An interface without greying-out (internalization) is expected to yield better performance in later phases, and better knowledge of the task. Subjects solved an isomorph of missionaries and cannibals in two conditions: with greyed-out items and without. It showed that externalization had little influence on performance. All subjects learned quite well how to solve the puzzle. On a knowledge test however, it turned out to be different. The procedural knowledge tested afterwards was equal, but declarative knowledge, concerning the rule central to what this problem was about, was worse for persons who had greyed-out items. Also, months later the same internalization-subjects had faster problem recognition of the task, and better performance on a similar task.