Feb 4 2013 Long Term Memory Week 5
Evidence for the distinction between explicit and implicit memory systems comes from
people suffering from amnesia
Explicit: We remember them, talk about
them. Implicit: unconscious, we think of
but we didn’t know we have it. Patients
with amnesia can lose one and still
have the other.
- Retrograde amnesia:
o Memory loss for events prior to trauma (injury).
o It is graded> Coming back slowly.
o Most memory loss just right before injury.
o Oldest memory is retained.
o Improves with time, but depends on severity of injury.
- Anterograde amnesia:
o Memory loss for events after trauma.
o Unable to form new memories.
o Does not improve overtime.
Seizures started at 10 years old. Feb 4 2013 Long Term Memory Week 5
By 27, they were so severe could no longer work – they became intractable
seizure disorder: can’t be treated.
Bilateral removal of medial temporal lobe in 1953
What causes a seizure? When all
neurons in the brain acting same
time in sync. It takes over the
activity of brain. It always starts in
one part of brain which recruits the
rest of the brain.
Successfully treated seizures
Intelligence, language, personality, and memory for past events relatively intact
Complete loss of ability to form new memories>> anterograde amnesia.
His short term memory was fine, it was the LTM that was a prob.
i.e. loss of memory consolidation
HOW COULD H.M. REMEMBER?
H.M. had lost all ability to form new explicit memories but demonstrated normal implicit
learning. He could do new things even if he didn’t have explicit memory
Memory for action
Tower of Hanoi Feb 4 2013 Long Term Memory Week 5
No associative: Refers to
habituation and sensitization.
Episodic: you vividly remember.
Semantic memory: Things you
know, the facts.
TYPES OF MEMORY TASK
Different types of tasks are used to measure different types of memory
Recall: asked to remember. Short
DECLARITIVE MEMORY Recognition: list of things you saw.
Atkinson-Shiffrin (1968) multi-store
(modal) model Serial recall: remember in the order
Free recall: remember in any order. Feb 4 2013 Long Term Memory Week 5
WHY DO WE FORGET
Serial Position Curve: memory is
good for the beginning and end of
list. Primacy effect: Have been
transferred to LTM. Recency Effect:
Items are in STM or working
Evidence that primacy and recency effects involve separate memory systems comes from
observation that we can eliminate one with the other.
Increasing the time between presentation and test would eliminate the recency effect.
Aserial recall task would eliminate the recency effect.
Increasing Presentation speed would reduce the primacy effect because you don’t have
time to rehearse.
Poor memory for items in the middle can be explained by decay theory and interference
Retroactive interference (RI): inhibitory effects of new information on old
information. Items are the beginning are influenced.
Proactive interference (PI): inhibitory effects of old information on new
information. Items at the end of the list are influenced. HOW DO WE EVER
LEARN ANYTHING NEW?
RELEASES FROM Proactive Interference.
Presented three words of
fruits. Made them counndbackwards
by 3 to prevent rehearsal. 2 time
again. 3 time again. Across trials
performance decreased. Proactive
interference. 4 trial: he divided
participants into 4 groups: fruits,
meat, vegie, profession. Release
from proactive interference
occurred. WHY? The three
categories have different meanin