Lecture 15 - Recognition Memory & EEG

Question 1

What is a recognition memory test?

Answer 1

• See objects and some have been encountered before and other have not.
• Which object have you encountered before?
• Also need to recognise some of the details of the event e.g in study phase, show ppt words on a screen - gap - memory testing after through words in study phase and random words too

Question 2

What is the signal detection model?

Answer 2

• Memory is a continuous variable
• Distribution is assumed to be normal and overlap (depends on manipulation of tasks)
• Response criterion: black line on graph. If it’s on the right, people will say it is old information regardless, and vice versa
• Discrimination sensitivity: is distance between two peaks: discrimination from old to new information
• Different criteria

Question 3

What was a notation that shows signal detection?

Answer 3

• Results: if item and response is old = hit, if response old and it is new = false alarm
• If response is new & item is old = miss, if item is new = correct rejection

Question 4

What are the dual process accounts?

Answer 4

• Familiarity: awareness of a prior encounter but with no recovery of contextual details
• Fast and automatic
• Modelled same as signal detection theory
• Recollection: recovery of contextual details e.g location.
• Slow & more attention demanding

Question 5

What is the evidence that are two processes that contribute to memory judgements?

Answer 5

• EEG & ERP evidence

Question 6

What is EEG?

Answer 6

• Electroencephalography
• Non-invasive that records electrical activity of the brain via oscillations
• Strength = excellent temporal resolution e.g to the millisecond
• Not very good at spatial resolution

Question 7

What was a study conducted for ERPs?

Answer 7

• Ppts were shown old and new items randomly intermixed and record their response whilst recording EEG (after study phase)
• Cut up EEG time locked to the onset of the item
• Average together trails of the same type e.g all the hits = memory signal should get stronger and noise will drop out

Question 8

What is ERP evidence for two memory processes?

Answer 8

• Relevant findings come from analyses of old/new effects
• Correct judgement with new word = baseline as non-memory is tested
• Contrast correct judgements to old and new (to test memory vs non-memory)
• If reliable ERP diff found = indicates we have an index of processes that reflect successful memory retrieval.

Question 9

What is the left-parietal ERP old/new effect?

Answer 9

• Onsets 400-500ms post-stimulus
• Largest at left-parietal scalp locations
• Duration of 500-800ms
• Index of recollection

Question 10

How does the left parietal old/new effect show recollection experimentally?

Answer 10

• Words presented visually or auditorily in study phase
• Tested all visually presented Ppts: ask if word is old/new & ask if heard/seen (source)
• ERP was larger when ppt made a correct source judgment compared to incorrect
• Shows recollection as source correct shows they remembered the context (source of how they received info)

Question 11

What is the mid-frontal ERP old/new effect and criterion?

Answer 11

• Studied effects of adopting tory/liberal decision criteria on mid-frontal effect
• Tory: asked to give old response when confident item is old
• Liberal: asked to new response only when confident
• Both criterions get pushed in opposite directions
• Index of familiarity
• Hits in tory condition were larger than liberal

Question 12

What did Yu and Rugg do?

Answer 12

• Aimed to electrophysiologically dissociate the neural correlates of recollection and familiarity (Combine both studies above)
• Used modified Remember/Know paradigm as a test
• For each judgment in the test phase, ppts asked why they feel they recognise the item
• Remember: consciously recollect particulars of study event e.g word was in red/emotions (recollection)
• Know: Feel they have seen item before but no memory for details of event (familiarity)
• Know split into two: confident/unconfident
• New: item has not been presented in study phase
• Prediction for mid-frontal old/new effect: Should covary with recognition confidence
• Prediction for left-parietal old/new effect: Elicited by ‘Remember’ items but not either class of old