Lecture 5 - LTM

Question 1

Features of LTM

Answer 1

• holds info for indefinite period of time
• seemingly limitless
• retrieval: process of recovering info from LTM into STM
• info can be lost from LTM

Question 2

STM vs LTM - same or different?

Answer 2

• if an individual performances normally on Task A, but is impaired on Task B, this is called a dissociation deficit.
• provides evidence to suggest that the two processes are DISTINCTIVE (eg impaired LTM, but normal STM)

Question 3

The case of H.M.

Answer 3

• had hippocampus removed to prevent epileptic seizures.
• operation cured epilepsy, but left him with amnesia.
• had severe anterograde amnesia: an inability to encode any new memories that occurred AFTER his operation.
• also retrograde amnesia: couldn’t remember much from the period 1-2 years prior to the operation.
• his STM as tested by the digit span task was within normal range
• suggests that LTM and STM are relatively independent - there is a dissociation between LTM and STM

Question 4

What is a double dissociation? K.F. Example

Answer 4

• as in H.M.’s case, a dissociation between STM and LTM was observed.
• if the opposite is also seen in another individual (impaired STM, but normal LTM), this is called double-dissociation. Stronger evidence of a dissociation…
• K.F. Had a digit span of two items, yet had a functioning LTM

Question 5

LTM deals with different info in different ways. How can we describe the different types of LTM?

Answer 5

• the type of knowledge that is being stored (procedural/ declarative)
• the way that this knowledge is expressed (implicit /explicit)

Question 6

Evidence for a dissociation between procedural and declarative LTM

Answer 6

• some individuals with Amnesia like H.M. are unable to remember any new declarative knowledge, yet are capable of learning new procedural knowledge.
• even if they don’t remember doing the task, their learning curves similar to normal participants.

Question 7

Evidence to suggest a double dissociation between procedural and declarative LTM

Answer 7

• individuals with dementia due to Huntington’s disease…

- remember doing a task repeatedly, but show no improvement in the task over time.

Question 8

Evidence of a double dissociation between semantic and episodic LTM memories

Answer 8

K.C. - motorbike accident: couldn’t encode new episodic memories but semantic memories largely unaffected.

Italian woman with brain damage: semantic memory impaired (couldn’t recall facts like the meanings of words), but episodic memory not impaired.

Question 9

Is there evidence that semantic and episodic memories closely connected, despite evidence of double dissociation a?

Answer 9

Yes!

• episodic memories can become semantic memories.
• parts of an episodic memory trace refer to semantic facts

Question 10

What is pragmatic inference?

Answer 10

• occurs when someone reads a sentence which leads them to expect or believe in something that was not explicitly stated.
• inferences based upon our prior knowledge.

Eg read the sentence: “the new baby STAYED AWAKE all night”
fill in the blank: “the new baby (stayed awake became CRIED) all night”

Question 11

Why does pragmatic inference occur?

Answer 11

• we don’t actually need to remember all the details of everything we see/hear/read. We can go by the ‘gist’ of the argument.
• the world is quite predictable. This leads us to be able to rely upon inferences and short cuts when encoding info.
• these short cuts can free up the brain for processing other important information.

Question 12

Does pragmatic inference show that memory is reproductive or reconstructive?

Answer 12

-memory is RECONSTRUCTIVE
-we reconstruct info based upon the original source info plus our prior expectations and knowledge.
Example, AJ - could recall events in incredible detail.