What evidence supports separability of the Phonological Loop and the Visuospatial Sketchpad?

• A. Double-dissociation findings and task-specific interference patterns.
• B. They always show identical impairment across modalities.
• C. Neuroimaging shows complete overlap in neural resources.
• D. There is no behavioral evidence for distinct subsystems.

Answer: (A)

The main idea being tested is that the Phonological Loop and the Visuospatial Sketchpad operate as separate components within working memory, and strong evidence for this comes from double dissociations and task-specific interference patterns.

Double dissociation means you can disrupt one system without affecting the other, and vice versa. In experiments, tasks that rely on the Phonological Loop (like remembering sequences of sounds or digits) are selectively impaired by manipulations that load or suppress phonological processing—while Visuospatial tasks remain relatively spared. Conversely, tasks that depend on the Visuospatial Sketchpad (like tracking locations or mental rotation) are selectively disrupted by visual or spatial interference, with phonological tasks largely unaffected. This pattern shows that each subsystem has its own resources and can fail independently, which supports their separability.

Understanding this helps clarify why simply finding a general impairment or overlapping neural resources wouldn’t fit the data as well. If there were a single shared resource or complete neural overlap, you wouldn’t see these clear, selective disruptions that spare one system while harming the other.