Human Cognitive Processes: psyc 345

Ch. 6 Long-term memory

Takashi Yamauchi© Takashi Yamauchi (Dept. of Psychology, Texas A&M University)

• (Q1) Is short-term memory and long-term memory anatomically and behaviorally separable? If so, how?

• (Q2) Which part of the brain is used for long-term memory, and how do we store long-term memory?

• (Q3) Are there different kinds of long term memory systems?

• (Q1) Is short-term memory and long-term memory anatomically and behaviorally separable? If so, how?

• (Q2) Which part of the brain is used for long-term memory, and how do we store long-term memory?

• STM vs. LTM– There are clear distinctions between STM and LTM. – STM and LTM interact constantly.

• Demonstration: – CogLab

• Serial position

Fig. 6-5, p. 182

memory is better for words presented at the beginning of the list (primacy effect) and at the end (recency effect)

Fig. 6-6, p. 183

The dashed curve occurred when the words were presented more slowly

no recency effect occurs if the memory test is delayed for 30 seconds (dashed line).

What does this tell?

• Primacy effect– Words are rehearsed during presentation of

the list, so they get into LTM

• Recency effect– Words are still in STM

Distinguishing STM and LTM: Neuropsychological evidence

• K. F. (described by Warrington et al.)– STM Impaired, LTM OK

• A left posterior temporal lesion– This resulted in an almost total inability to

repeat verbal stimuli (digits, letters, words, and sentences)

Memory

• H. M. – his hippocampus is surgically removed.

• Impaired:– H. M. cannot retain information about events

that happened after the operation.

• Intact– intelligence (IQ), attention, concentration,

language and motivation levels were intact.– good memories about several weeks before

the operation.

Hippocampus

Selectivity of memory loss

• H. M.– before the operation– remembered which elementary school he

went, the names of friends in his high school days, TV programs he saw when he was a child.

– Had no idea about what he did, whom he met, what he saw, and what he talked last months, last week, or even a few hours ago.

H.M.

• Memory dissociation– H.M.’s IQ 118– Language comprehension normal– Motor learning normal– Problem solving and practice normal– H.M. had good memory about the events and

incidents he experienced before the surgery.– H.M. hardly remember what happened to him after

the surgery

H.M. (continued)

• H.M. was severely impaired in one type of memory,

• such as the memory about specific events,

– but his memory about motor skills and other learning is intact.

Mirror-reversed word triad

• (Q3) Are there different kinds of long term memory systems?

• Organization of LTM

Declarative (explicit) vs. Implicit memory

• Declarative (explicit) memory– Is our conscious recollection of events or facts

we have learned

• Implicit memory– Memory without conscious awareness

• Episodic: memory for personal events–Episodic involves mental time travel

–You can trace down the time frame of your episodic experience.

• Semantic: facts and knowledge–Semantic memory does not involve

mental time travel

The separation of episodic & semantic memories

• Episodic can be lost, leaving only semantic– Acquiring knowledge may start as

episodic but then “fade” to semantic

• Semantic memory can be lost, while episodic memory is intact.– A brain damaged patient knows what

she did yesterday, or 10 days ago but don’t remember meanings of words.

Separate brain activation for episodic and semantic memory

• Fig. 6.8

Blue areas are associated with semantic memory

Connection between Episodic & Semantic Memories

• Semantic Memory can be enhanced if associated with episodic M.– Personal semantic memory: semantic

memories that have personal significance

• Episodic Memory can be enhanced if associated with semantic M.– Extracting meaning (e.g., story)

enhance our memory.

Implicit memory

• Implicit memory– Memory without conscious awareness

• CogLab

• Implicit learning

Neuropsychological evidence

• Movie:

• DVD: How does your memory work? (chapter 3; 7:09)

Implicit or Explicit Memory Tasks

• Explicit memory tasks– Involves conscious recollection– Participant knows they are trying to retrieve

information from their memory

• Implicit memory tasks– Require participants to complete a task– The completion of the task indirectly indicates

memory

implicit memory tasks

• Mirror tracing

• Mirror reversed reading

• Identifying degraded words• http://www.psywww.com/intropsych/

ch06_memory/implicit_vs_explicit_memory.html

Tulving, E., Schacter, D. L., Stark, H. A. (1982).

• Priming and implicit memory

• Test implicit memory and explicit memory– Stimuli:

• 96 words

– Design:• 3 phases: Learning phase & test phase (1hr)• & test phase (7 days later)

Tasks

• Phase I (Learning)– Ss studied 96 words (5sec/word)– Ss were told that they would be tested with

their recognition memory.– Ss could study the words in whatever way

they like.

Fig. 6-10, p. 194

Learning a new skill: mirror-reverse reading

Mirror-tracing Reading degraded words

Warrington (1968)

• 5 patients with Korsakoff’s syndrome – deficit in declarative memory

• Give them incomplete pictures and let them learn how to identify the fragmented pictures.

Fig. 6-11, p. 194

Show (a), and then (b), (c),.. so on until they were able to identify the picture

Fig. 6-12, p. 195

Implicit memory in everyday experience

• Mere exposure effect / propaganda effect

• You form a positive feeling to things that you experienced before.

Perfect & Askew (1994)

• Participants scanned ads in a magazine.

• They rated how appealing the ads were.

• Results: Participants gave higher ratings to the ones they had been exposed to than to the ads they had never seen.

• This happened even when they recognized 2.4% of the original 25 ads.

• Masked priming: demonstration• http://www.u.arizona.edu/~kforster/priming/

index.htm

H.M.

• Memory dissociation– H.M.’s IQ 118– Language comprehension normal– Motor learning normal– Problem solving and practice normal– H.M. had good memory about the events and

incidents he experienced before the surgery.– H.M. hardly remember what happened to him after

the surgery

Hippocampus

Initial state

Goal state

• Tower of Hanoi solution

• http://www.youtube.com/watch?v=aGlt2G-DC8c

• H. M got better at doing the Tower of Hanoi game even though he did not remember at all about his previous trials.