Evidence for a Latent Bottleneck After Extensive Dual-Task Practice of a Visual-Manual and an Auditory-Verbal Task

Area of Science:

• Cognitive Psychology
• Human Performance

Background:

• Dual-tasking often leads to performance impairments, known as dual-task costs.
• Practice can mitigate these costs, improving dual-task performance compared to single-task performance.

Purpose of the Study:

• To empirically test the latent bottleneck model's explanation for practice-related improvements in dual-task performance.
• To investigate how practice affects processing stages within a dual-task context.

Main Methods:

• Participants engaged in extensive practice of simultaneous visual-manual and auditory-verbal tasks under single-task and dual-task conditions.
• After practice, the duration of response selection stages was manipulated.
• The impact of these manipulations on reaction times (RTs) during transfer was analyzed.

Main Results:

• A pattern of selective RT prolongations was observed, contingent on the manipulated process's location relative to a latent bottleneck.
• Manipulations at bottleneck stages of the longer (auditory-verbal) task did not affect RTs of the shorter task.
• Manipulations at bottleneck stages of the shorter (visual-manual) task did propagate into the longer task's RTs post-practice.

Conclusions:

• The observed pattern of reaction time changes supports the latent bottleneck model.
• Dual-task practice leads to adaptive changes in processing bottleneck stages, explaining performance improvements.