The influence of interface attributes and interaction elements on user performance and cognitive load in task interruption scenarios

This study aims to investigate the mechanisms by which digital interface attributes (interface complexity and similarity) and interaction elements (contextual guidance during the task resumption phase) influence user task performance and cognitive load in task interruption scenarios. A within-subject experimental design was employed, where participants were required to switch between primary and interrupting tasks while completing designated arithmetic tasks, thereby simulating real-world task interruptions. The results indicate that interface complexity is a key factor affecting task performance and cognitive load. High-complexity interfaces significantly prolonged task resumption lag times, increased error rates, and led to higher levels of cognitive load. The effect of interface similarity on performance showed a significant interaction with complexity. Under high complexity conditions, high-similarity interfaces increased resumption lag times; conversely, under low complexity conditions, high-similarity interfaces reduced resumption lag times. Furthermore, providing clear contextual guidance significantly shortened resumption lag times during the task resumption phase and reduced the number of selection errors, although it did not have a sufficiently significant impact on cognitive load. Despite the varying influence of each variable on resumption performance, the overall performance can be explained by the Memory for Goals Theory (MFG). The findings offer valuable theoretical and practical guidance for optimizing interface design in complex task environments, underscoring the importance of considering interface complexity, similarity, and resumption guidance when designing multitasking interfaces.