Opportune moments for task interruptions: examining the cognitive mechanisms underlying interruption-timing effects

Area of Science:

• Cognitive Psychology
• Human-Computer Interaction
• Task Interruption Research

Background:

• Task interruptions during high mental workload are known to be more detrimental than during low mental workload.
• Understanding the precise timing of interruptions and their impact on performance is crucial for optimizing task design and minimizing errors.

Purpose of the Study:

• To investigate the effects of interruption timing on primary task performance using a theory-driven approach to define mental workload.
• To examine how different interruption points within a sequential task influence resumption costs.

Main Methods:

• Participants completed a six-subtask primary task, with interruptions occurring before the second, third, or fourth subtask.
• Task sequences were structured as either lag-2 repetition triplets or lag-2 switch triplets to manipulate mental workload and subtask inhibition.
• Resumption costs were measured by comparing performance on subtasks after an interruption to performance on the same subtasks in non-interrupted sequences.

Main Results:

• A significant interruption-timing effect was observed, with higher resumption costs when interruptions occurred before the third subtask.
• Interruptions before the second and fourth subtasks resulted in lower resumption costs compared to interruptions before the third subtask.
• The observed interruption-timing effect on resumption costs did not differ between lag-2 repetition and lag-2 switch sequences.

Conclusions:

• The timing of task interruptions significantly influences performance recovery, with mid-sequence interruptions being particularly disruptive.
• Findings suggest that the cognitive load associated with task sequencing, particularly overcoming subtask inhibition, plays a key role in interruption costs.
• Results are discussed in relation to memory retrieval and context reconstruction theories to explain performance decrements after interruptions.