Effects of complexity and similarity of an interruption task on resilience toward interruptions in a procedural task with sequential constraints.

The goal of the present study was to examine effects of complexity and similarity of an interruption task on postinterruption performance in an 8-step procedural task with sequential constraints. In Experiment 1, the primary task was interrupted between different steps with 1 of 4 versions of n-back task, which differed in complexity (simple, complex) and similarity in processing codes (verbal, spatial) to the primary task. After the interruption, participants (N = 44) had to resume the primary task as quickly as possible with the next correct step, that is, the 1 following the step after which the interruption occurred. Postinterruption performance in terms of resumption times, sequence errors and nonsequence errors was assessed. Results of Experiment 1 revealed longer resumption times and more sequence errors after complex interruptions compared to the simple ones. However, effects of processing-code similarity were less clear. For assessing the effects of similarity in processing codes again in Experiment 2, participants (N = 41) performed the same primary task and were interrupted with a verbal or a spatial classification task. The results revealed no significant effect of processing code on the postinterruption performance. Moreover, a posthoc analysis revealed that 1-back (sequential) interruption led to longer resumption times compared to the classification (nonsequential) interruption. Overall, our results revealed strong and consistent detrimental effects of interruption complexity on the postinterruption performance and no effect of similarity in processing codes. Finally, we provide preliminary evidence that similarity in sequential structure between the tasks can influence the resilience toward interruptions