Designing consistent procedures is greatly emphasized to reduce the cognitive complexity that users of software programs and electronic devices must face. It becomes more difficult, however, to achieve consistency as more functions are included in such systems. This article shows experimentally that the effects of consistency depend on the semantic affinity among corresponding tasks that users recognize. It was found
that, when performing a task, the user tended to reconstruct the task procedure out of semantic affinity rather than remembering procedures for individual tasks. Another experiment demonstrated that the recognition of affinity could be affected by the design of the user interface. State closures (i.e., the modes in which a group of functions are available) were shown to be particularly influential to recognized affinity and to the expectation of procedural similarity. The results imply corresponding design principles regarding consistency, task knowledge, and the interface.