double dissociation

Double dissociation

occurs when two different cognitive abilities can be independently impaired, providing evidence that they rely on at least partially separate processes or systems

Patient A had preservced memory ability X but preserved ability Y → Patient B has preserved ability X but impared ability Y

• Patient A might struggle to consciously remember practicing a skill but still improve at that skill with practice.

• Patient B might consciously remember instructions and experiences but struggle to acquire certain motor skills.

 Double dissociation provides evidence that

two cognitive functions are at least partly independent.

If both memory abilities depended entirely on the same mechanism,

it would be harder to explain why they can be selectively impaired in opposite patterns