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The n-back as a dual-task: P300 morphology under divided attention
S Watter1, G M Geffen, L B Geffen
1Cognitive Psychophysiology Laboratory, The University of Queensland, Australia. swatter@s.psych.uiuc.edu
Psychophysiology
|September 21, 2002
Summary
The n-back task functions as a dual task, increasing working memory load while keeping matching task demands stable. This impacts attention allocation, crucial for interpreting n-back task results.
Area of Science:
- Cognitive Neuroscience
- Psychology
- Neuroscience
Background:
- The n-back task is widely used to assess working memory capacity.
- Its dual-task nature, however, requires careful consideration for accurate interpretation.
Purpose of the Study:
- To investigate the n-back task as a dual task.
- To differentiate between working memory and embedded subtask demands.
- To analyze the impact of increasing memory load on cognitive processes.
Main Methods:
- Participants performed the n-back task with varying memory loads (0, 1, 2, or 3 back).
- Visual targets were presented at pseudorandom positions.
- Event-related potentials (ERPs), specifically P300 latency and amplitude, were measured.
Main Results:
- P300 peak latency remained constant, indicating stable perceptual and cognitive demands of the matching subtask.
- P300 peak amplitude decreased as memory load increased.
- This decrease reflects a shift in attention and processing resources towards working memory.
Conclusions:
- The n-back task exhibits dual-task characteristics, engaging both working memory and an embedded matching task.
- Cognitive resources are reallocated from the matching subtask to working memory with increasing load.
- These findings emphasize the importance of considering the dual-task nature of the n-back paradigm in research.