Week 4: Memory Disorders

Question 1

Retrograde amnesia

Answer 1

Poor recall for memories BEFORE onset of amnesia

Question 2

Anterograde amnesia

Answer 2

Loss of ability to form new memories AFTER onset of amnesia

Question 3

Global amnesia

Answer 3

Severe anterograde amnesia, moderate retrograde amnesia

Question 4

Temporal gradient

Answer 4

Older memories are less impaired than newer memories

Question 5

Korsakoff’s syndrome (aka deincephalic amnesia)

Answer 5

Caused by vitamin B1 deficiency from chronic alcoholism. Experience poor ability to remember events before and after onset of amnesia

Question 6

Semantic dementia

Answer 6

Severe problems with SEMANTIC memory (e.g. information about
meanings of words and concepts) but intact episodic memory. Always involves
degeneration of the ANTERIOR TEMPORAL LOBE.

Question 7

Dissociation

Answer 7

Identification of a SINGLE brain region responsible for a cognitive process

Question 8

Single dissociation

Answer 8

Identify that brain damage to one structure disrupts one cognitive
process but not another.

Question 9

Double dissociation

Answer 9

Identify that brain damage to one structure disrupts one cognitive
process (‘X’) but not another (‘Y’). Also, identify that brain damage to different structure
disrupts cognitive process ‘Y’ but not ‘X’.

Question 10

Misinformation effect

Answer 10

Refers to the finding that memories are easily distorted by misleading info presented after

Question 11

Confirmation bias

Answer 11

Tendency to recall information in a way that confirms pre-existing beliefs.

Question 12

Brain structures and episodic and semantic memory (recap)

Answer 12

Damage hippocampus = episodic affected

Damage para-hippocampal cortex = semantic affected

Damage to both brain regions = both memory poor

Question 13

Potential causes of amnesia:

Answer 13

• surgery (e.g. patient HM)
• chronic alcohol abuse
• brain tumours
• bilateral stroke
• encephalitis (brain swelling, typically due to infection)
• Dementia (Alzheimer’s disease)
• Closed head injury

Question 14

Retrograde amnesia

Answer 14

Poor recall of memories formed BEFORE onset of amnesia.

(Greater impact on episodic (personal) than semantic memories (general knowledge)).

TEMPORAL GRADIENT - older memories less impaired than newer ones

Question 15

Explanations for temporal gradient:

Answer 15

CONSOLIDATION THEORY:
- Physiological process in the hippocampus leads to formation of long-lasting memories
- consolidated memories stored elsewhere, protecting them from effects of hippocampal damage (= memories in there a longer time = less likely to lose)

SEMANTICISATION:
- Episodic memories become more like semantic ones over time (less personal, more vague) = older memories protected from effects of brain damage…

REDUCED LEARNING OPPORTUNITY:
- episodic memories depend on a single learning experience = reduced learning opportunity explains emnesia
- semantic memories depend on several learning experiences (e.g. taught some facts more than once)

Question 16

Anterograde amnesia

Answer 16

Loss of ability to form new memories AFTER onset of amnesia

* Results from damage to the areas of the brain that are involved in forming new memories
* Damage to the hippocampus the main cause in most instances
* Mammillary bodies and fornix also commonly involved

Question 17

Global amnesia

Answer 17

• Moderate retrograde amnesia and severe anterograde amnesia
  
  • Results from lesions of structures in the medial temporal lobe, specifically the hippocampus
  • Patient HM

Question 18

Patient H.M.

Answer 18

• most studied amnesiac patient
• suffered from severe epilepsy from age 10
• at 27yrs, had surgery to remove the entire medial temporal lobe (including hippocampus)
• moderate retrograde and severe anterograde amnesia (global amnesia)

Question 19

Korsakoff’s syndrome

Answer 19

AKA diencephalic amnesia

• vitamin B1 deficiency from chronic alcoholism
• ## damage to mammilary bodies in hypothalamus

    – Poor ability to remember events before and after onset of amnesia
    (retrograde & anterograde)
    – Some new learning ability (e.g. motor skills)
    – Slight impairment of STM (e.g. digit span)

Question 20

Symptomology of Korsakoff’s syndrome & issues

Answer 20

• Typically had gradual onset – Events happened before or after amnesia onset?
• Brain damage widespread (hippocampus and frontal) – damage to frontal lobes = other cognitive deficits
• Precise pattern of damage varies across patients – difficult to generalise across patients
• Brain plasticity and learning of compensatory strategies – does not provide a direct assessment of the impact of brain damage of the LTM

Question 21

Semantic dementia

Answer 21

Severe problems with semantic memory, but intact episodic memory

• loss of info on meaning of words/concepts
• difficulty naming pictures/objects, single word comprehension, categorising, and knowing the uses of objects

Episodic memory and most executive functions (e.g. attention) reasonably intact in the early stages

* Always involves degeneration of the anterior temporal lobe
	– Where semantic memories are stored – Perirhinal and entorhinal cortices where semantic memories formed

Question 22

Double dissociation

Answer 22

Amnesia and semantic dementia point to a double dissociation in LTM

Amnesia = hippocampus
– Poor episodic memory (‘X’)
– Intact semantic memory (‘Y’)

Semantic dementia = anterior temporal lobe
– Poor semantic memory (‘Y’)
– Intact episodic memory (‘X’)

Question 23

Eyewitness testimony

Answer 23

The Innocence Project (2008) “Eyewitness misidentification is the single greatest cause of wrongful convictions nationwide, playing a role in more than 75% of convictions overturned through DNA testing.” Still, the criminal justice system profoundly relies on eyewitness identification and testimony for investigating and prosecuting crimes.
(Wells & Olson, 2003)

Question 24

Memory errors (3)

Answer 24

• forgetting
• intrusions
• bias

Question 25

Forgetting

Answer 25

DECAY or INTERFERENCE Decay: memory traces of STM fade over time, less info for retrieval Interference: similar info gets in the way of other info - Retroactive - more recent info gets in the way of trying to recall older info - Proactive - previously learned materials get in the way of trying to recall newer materials

Question 26

Intrusions

Answer 26

Mistakes in which elements not part of original memory trace get mixed-up or intrude recall...

Question 27

Intrusion: DRM paradigm

Answer 27

named after Deese, Roediger and McDermott; recall words semantically linked with list of words, that may not even be in a list. (e.g. bed, rest, awake, peace, night, tired, snooze) Even tho not in the list, people may recall 'sleep'

Question 28

Misinformation effect

Answer 28

- memories distorted by info after an event SOURCE MISATTRIBUTION: - occurs when memories from one source resembles those from another - overlapping

Question 29

Loftus & Palmer (1974)

Answer 29

“How fast were the cars going when they […] into each other?” * Smashed Estimated speed = 41mph * Hit Estimated speed = 34mph ------------------------------------- “Did you see any broken glass?” * Yes = 34% Smashed * Yes = 14% Hit Demonstrates that memory is fragile – can be distorted by changing just one word!

Question 30

Bias

Answer 30

Memory influenced by prior expectations! CONFIRMATION BIAS: - recall info confirming existing beliefs - schemas can lead us to form expectations - CONFIRMATION BIAS - UNCONSCIOUS TRANSFERENCE - OTHER-RACE EFFECT - AGE - WEAPON FOCUS

Question 31

Tuckey & Brewer (2003) Showed a film of a bank robbery... findings?

Answer 31

- recalled info successfully related to bank robbery schema: male, disguises, demanded money - less likely to recall info not related to the schema; the colour of the getaway car

Question 32

Face recognition: Unconscious transference

Answer 32

Misidentify a familiar (but innocent) face as being responsible

Question 33

Face recognition: Other-race effect

Answer 33

recognition for same-race faces generally more accurate than other-race faces

Question 34

Face recognition: Own-Age bias

Answer 34

more accurate when culprit is similar age to witness

Question 35

Anxiety and violence: Weapon focus

Answer 35

- narrowing of attention to important stimuli - reduces memory of peripheral details = weapon focus

Question 36

Avoiding memory errors - a method:

Answer 36

Cognitive interviews: 1. mental reinstatement of env 2. encourage reporting of every detail (ENCODING SPECIFICITY PRINCIPLE) 3. describe the incident in different orders 4. reporting the incident from different view-points (different retrieval routes)