long term memory and the amnesias Flashcards
(15 cards)
What are the two main types of long-term memory?
Declarative (Explicit) Memory – “Knowing what, why, where, and when”
Non-Declarative (Implicit) Memory – “Knowing how”
What is declarative memory?
Conscious recollection of facts, events, and locations
Autobiographical (episodic) and factual (semantic)
Hippocampus-dependent
What is non-declarative memory?
Unconscious memory for skills, habits, and learning
Includes motor and cognitive skills
Not dependent on the hippocampus
What are the subtypes of declarative memory?
Episodic memory: Vivid, first-person memory of personal events (“mental time travel”)
Semantic memory: General factual knowledge, including concepts and self-knowledge
What are the subtypes of non-declarative memory?
Procedural memory: Skills like bike riding, typing
Priming: Faster stimulus identification due to prior exposure (e.g., “nurse” primes “doctor”)
Classical/Operant conditioning: Associative learning
Non-associative learning:
Habituation – ignoring repeated, irrelevant stimuli
Sensitization – increased attention to threats
What is retrograde amnesia?
Loss of past memories acquired before brain injury
Temporally graded: older memories are more preserved
What is anterograde amnesia?
Inability to form new declarative memories after brain injury
Example: Patient H.M. – could not form new episodic or semantic memories post-surgery
What happened in H.M.’s case (Scoville & Milner, 1957)?
Bilateral removal of hippocampi
Result:
Severe anterograde amnesia – no new episodic/semantic memory
Temporally graded retrograde amnesia – lost recent memories, preserved childhood memories
What does H.M.’s case show about the hippocampus?
Critical for consolidating new declarative memories
Not necessary for procedural memory (he improved in mirror-tracing)
Famous quote from H.M. (Milner, 1966):
“It’s like waking from a dream; I just don’t remember.”
How does amnesia support the distinction between memory types?
Declarative memory impaired (episodic/semantic)
Non-declarative memory intact (skills, priming, conditioning)
What could H.M. still do?
Learn procedural tasks (mirror tracing)
Show priming effects (e.g., lexical decision tasks)
Display normal classical conditioning
Other supporting evidence:
Korsakoff’s syndrome patients
ECT patients
Anoxic encephalopathy patients
Key study: Graf, Squire, & Mandler (1984)
Amnesics showed normal priming despite explicit memory deficits → supports dissociation
Tests for non-declarative memory:
Mirror-tracing task
Lexical decision task
Conditioning paradigms
