Limits on selecting multiple items from working memory: the role of context and item competition

Area of Science:

• Cognitive Psychology
• Neuroscience
• Human Memory

Background:

• Working memory (WM) is crucial for goal-directed behavior, requiring flexible and efficient content access.
• Simultaneous selection of multiple WM contents is slower and more error-prone than single-item selection.
• Prior research indicates a performance decline in multi-item WM access, but the underlying mechanisms remain unclear.

Purpose of the Study:

• To investigate the mechanisms causing the performance decline in multi-item working memory selection.
• To differentiate between competition among memory items versus competition among context representations as the source of the selection bottleneck.
• To clarify the principles guiding the simultaneous retrieval of multiple contents from working memory.

Main Methods:

• Utilized a spatial retrocuing paradigm across five experiments.
• Independently manipulated the number of cued spatial locations (contexts) and the number of to-be-selected memory items.
• Measured selection speed and accuracy to assess performance.

Main Results:

• Cueing two spatial locations significantly delayed selection compared to cueing one, irrespective of the number of relevant items.
• The number of relevant items (set size) had a smaller and less consistent impact on selection speed.
• These findings consistently point to spatial context competition as a primary factor.

Conclusions:

• The bottleneck in multi-item working memory selection stems from the cognitive load associated with using multiple spatial contexts for retrieval.
• Efficient working memory relies on managing contextual information to access multiple memory contents simultaneously.
• Future research should explore strategies for mitigating context-driven competition in working memory.