The Influence of Interface Style on Problem Solving

According to a recent theory by Hayes and Broadbent (1988), learning of interactive tasks could proceed in one of two different learning modes. One learning mode, called S-mode, has characteristics not unlike what traditionally has been called “Insight learning”. The other mode, called U-mode, is in some respects like trial and error learning. Extending the theory to human-computer interaction, it predicts different problem-solving strategies for subjects (Ss) using command and direct manipulation interfaces. Command interfaces should induce S-mode learning, while direct manipulation should not do this. The theory was supported by two experiments involving the tower of Hanoi problem. Ss with a command interface made the least number of errors, met criterion in the least number of trials and used the most time pr. trial. They were also more able to verbalize principles governing the solution of the problem than Ss using a direct manipulation interface. It is argued that the theory may explain the “feeling of directness” that goes with good direct manipulation interfaces. Further, the results indicate that user friendliness, as this is traditionally measured, in some cases may prove to reduce the users' problem-solving ability.