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Memory Systems and double dissociation

Can someone please explain in detail please the term double dissociation in layman's terms and also help on how this is related to brain damage. Please also explain what is repetition priming, declarative memory, implicit vs explicit memory, when is memory episodic or semantic, retrograde and antrograde amnesia. How does all this related, especially double dissociation.


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To understand double dissociations and their importance to cognitive neuroscience, you have to remember that different cognitive functions are located in different areas in the brain. For example you have Broca's area which is involved with speech production. And you have Wernicke's area which is involved with language comprehension. But how can you tell when the function of one area is really its own, independent function? You can tell by finding double dissociations.

If someone gets brain damage in Broca's area, but not in Wernicke's area, they lose the ability to speak, but they keep the ability to understand language. If they get brain damage in Wernicke's area, but not Broca's area, they lose the ability to comprehend language but can still vocalize words and word-like sounds (but since they can't understand language, it comes out as "word salad"--jumbled up words that don't make any sense). So we can say that we have found a double dissociation between speech production and language comprehension. That is each of them can be dissociated from the other. And so we can ...

Solution Summary

Explains the distinctions between semantic and episodic memory, declarative and procedural memory, and implicit and explicit memory. Also explains the logic of double dissociation for cognitive neuroscience and its application for positing different memory systems.