| Popis: |
Slip errors can have severe consequences but are notoriously difficult to reduce. Training, visual cues and increasing motivation are generally not effective in eliminating these slips. Instead, the approach this work takes is to identify which steps in a routine task are most error prone, so that these can be designed out of device interactions. In particular, device- and task-oriented steps are investigated. Device-oriented steps are "extra" steps imposed by the device that do not directly contribute towards the task goal. Conversely, task-oriented steps directly bring the user closer to their goal. The main hypothesis addressed in this work is that device-oriented steps are more problematic than task-oriented ones. The concepts of device- and task-oriented steps are investigated more closely, by analysing the literature on routine action and mental representations of different steps. The core diff erence between the steps is found to be how relevant a step is to the goal. This is further supported by two qualitative studies. A series of experimental studies investigates the cognitive mechanisms underlying device and task-oriented steps. This is addressed through six experiments that address error rates, step times, proportion of omissions and sensitivity to working memory load. Participants learned one of three routine tasks, with several carefully controlled device- and task-oriented steps. The results show that on device-oriented steps, error rates are higher, step times are longer, the proportion of omissions is greater, and working memory load has an increased effect. These findings support the hypothesis that activation levels are lower on device-oriented steps. The thesis concludes that a step's relevance to the task goal plays an important role in the occurrence of errors. This work has implications for both our understanding of routine procedural action as well as the design of devices. |
