In a series of studies, researchers tested patient H.M., who had his hippocampus and surrounding medial temporal lobe surgically removed to treat severe epilepsy. After surgery, H.M. could recall events from before the operation and could carry on a conversation, but he could not remember new acquaintances even after meeting them dozens of times. Surprisingly, he could learn new motor skills like mirror tracing, even though he had no memory of practicing them.
H.M.'s improvement on mirror tracing without conscious recollection demonstrates the existence of which type of memory?
- A
Episodic memory
- Bcheck_circle
Implicit (nondeclarative) memory
- C
Flashbulb memory
- D
Semantic memory
Explanation
Procedural skills are stored as implicit (nondeclarative) memories, which do not require conscious recall and rely on the cerebellum and basal ganglia rather than the hippocampus. Episodic, semantic, and flashbulb memories are all explicit.