Task-evoked pupillary response to mental workload in human-computer interaction

Accurate assessment of a user's mental workload will be critical for developing systems that manage user attention (interruptions) in the user interface. Empirical evidence suggests that an interruption is much less disruptive when it occurs during a period of lower mental workload. To provide a measure of mental workload for interactive tasks, we investigated the use of task-evoked pupillary response. Results show that a more difficult task demands longer processing time, induces higher subjective ratings of mental workload, and reliably evokes greater pupillary response at salient subtasks. We discuss the findings and their implications for the design of an attention manager.