Usability enhancement based on usability heuristics: An examination of the underlying mechanism utilizing the...

User Interface (UI) design practices often abide by popular usability heuristics such as Nielsen's (1994) "10 usability heuristics for user interface design" or Gerhardt-Powals' (1996) cognitive engineering principles. To examine the underlying mechanism of user performance enhancement by following some of these usability heuristics, we compared user performance between two device conditions: one representing design practices following two selected sets of usability heuristics (experimental condition) and the other without following them (control condition). As a research framework, we adopted the psychological-refractory-period (PRP) paradigm along with the locus-of-slack logic, a well-established dual-task paradigm for examining the nature of cognitive benefits caused by experimental manipulations. Results showed that the experimental-device condition that followed the usability heuristics yielded faster performance than the control condition, especially when the stimulus-onset-asynchrony between the two tasks was long than when it was short. According to the locus-of-slack logic, these results suggest that the nature of cognitive benefits caused by following the usability heuristics is more likely to be due to shortening of the response-activation stage (rather than the response-selection stage). These findings suggest that following the two usability heuristics tends to facilitate a specific stage of the information processes more than other stages.