lecture 8 - False memories

Question 1

explain the memory model

Answer 1

sensory memory

to (attention)

short term memory

working memory (rehearsal)

to (encoding and retrieval)

long term memory

Question 2

what is a false memory

Answer 2

Defined as: “either remembering events that never happened, or remembering them quite differently from the way they happened” (Roediger & McDermott, 1995, p.803)

Question 3

describe the method of Roediger and mcdermotts 1995 - Experiment 1

Answer 3

examined false memory for related prototype words

• 6 lists of 12 words were presented audtitorially (1 word per 1.5 seconds) followed by a free recall of each list
• saw a list of words and pps rated confidence that each word was on the list (1-4)

lists were composed of 12 related words linked by an omitted prototype word
- examining recall of unsustained ‘critical lure’

Question 4

explain the results of Roediger and mcdermotts 1995 - Experiment 1

Answer 4

• free recall produced a serial position curve
• recall of words = 0.6

recall of unrelated words = 0.14 (non studied)

recall of critical words = 0.4(non studied)

False memory effect not due to guessing
58% of participants used highest confidence rating (4 = sure that the item was old) for the non-studied critical lure
Whereas 80% of non-studied unrelated words received the lowest confidence rating (1 = sure it was new)

Question 5

explain why roediegar and mcdermott did the 2nd experiment

Answer 5

The absence of a false memory signature in meta-cognition is important
…
Imagine a witness in a court of law … a confident witness would appear more convincing to a jury

But there is a weak correlation between confidence and eyewitness accuracy (Sporer et al., 1995)

Consider how flashbulb memory for an event (or crime) might be susceptible to false memory and misleading confidence

Question 6

explain roediegar and mcdermotts study

Answer 6

• As DRM study list is presented a ‘gist’ (general meaning) is developed

Subsequent accurate recall depends upon item-specific memory and ‘gist’

Whereas false memory relies upon ‘gist’ but not item-specific memory

Gist and item-specific recollection can exist in parallel (Brainerd & Reyna, 2005)

Accurate DRM performance necessitates distinguishing between gist and item specific recollection

Question 7

explain the associative networks of roediegar and mcdermotts stud

Answer 7

Associative networks: seeing a particular word (e.g. ‘plant’) activates related words (e.g. ‘tree’)
The critical word is repeatedly activated in these associative networks and the participant may claim to recall it
Importantly this is not simply an increased familiarity effect (as ‘R’ responses)

Question 8

what was lodtus and palmers study based upon

Answer 8

false memorys in an applied forensic setting

Question 9

explain the method of loftus and palmers study

Answer 9

False memory from a witness can result in a conviction

(Loftus & Palmer, 1974)
Participants saw video of an accident and then estimated speed of impact following different vocabulary

Question 10

explain the results of loftus and palmer

Answer 10

Contacted = 31.8mph
Hit = 34mph
Bumped = 39.3mph
Smashed = 40.8mph

There was no broken glass in the footage but … for those that heard ‘hit’, 14% said they saw broken glass
… for those that heard ‘smashed’, 32% said that they saw broken glass

Question 11

explain loftus and palmers study on memory malleability

Answer 11

Loftus (1975) subjects viewed film (no barn in film)
“How fast was the white sports car going when it passed the barn while traveling along the country road?”

assessd a week after the experiment about seeing a barn

Question 12

what are the results of loftus and palmers study on memory malleability

Answer 12

Week later
17% who were asked the misleading question reported seeing a barn
3% asked the control question reported seeing a barn

Question 13

what is the method of Loftus and Pickrell (1995) study of if you can get people to have memories of events that never happened

Answer 13

Interviewed relatives to generate 3 true stories and one false story about being lost while shopping as a child
Given the stories and asked to recall what they could of the events

Question 14

what are the results of the study on of Loftus and Pickrell (1995) study of if you can get people to have memories of events that never happened

Answer 14

68% recall of true events
29% recall of false events

True memories were rated as more clear and more words were used to describe them in recall

Question 15

explain the results of Hyman, Husband, and Billings (1995) study

Answer 15

Hospitalization, birthday/clown, wedding/punch, evacuate/store

80-90% of true events
no false events recalled in first interview
20% in a second interview
Some participants elaborated upon their false memories (added details never presented)

Question 16

why are falses memories so important in forensic settings

Answer 16

1980s and 1990s spate of criminal trials premised on the recovery of lost memories following therapy
View that following trauma, unpleasant memories are repressed but can later be retrieved intact (e.g. Tarr, 1994)

But might these ‘memories’ arise from suggestive techniques during therapy

Question 17

what is a suggestive technique during therapy

Answer 17

making people remember things that didn’t happen

Question 18

what did baioui investigate

Answer 18

whether we can differentiate a memory which is false from a real one

Can you differentiate between true and false memories by physiological responses?

Question 19

what did baioui hypothosise

Answer 19

“a stimulus that a person has already encountered bears higher significance than a completely unknown stimulus … We therefore hypothesize that stimuli that have been falsely recognized bears less significance than comparable correctly recognized stimuli … reflected in smaller electrodermal responses for falsely as compared to truly recognized stimuli” (p. 2)

Question 20

what physiological measures can be used to test whether a memory is real or fake

Answer 20

HR, skin concordance, respiration etc.

Question 21

describe the methodology usd by baioui 2012

Answer 21

• pictorial DRM task
• semantically related component removed from the image
• 20 min retention interval (completed a filler personality questionnair)
• critical lure included a test

Question 22

what are the results of baioui et al 2012

Answer 22

Standard false memory effect reported
- Higher recognition for related lures compared to unrelated (non-studied) items

• Stronger physiological effects for the true memories versus the false memories (lures)
• Some awareness that the ‘lure’ is false

Question 23

what did Cabeza et al. (2001) investigete

Answer 23

Neural mechanisms of false memory using fMRI

Question 24

what was the method used by Cabeza et al. (2001)

Answer 24

List of associated words presented:
“cucumber, pea, potato, onion …”

Different voices alternated for each list

At test participants performed recognition test on three different word conditions …

Question 25

what were the three word condiditions used by Cabeza et al. (2001)

Answer 25

True Items: items from the list (“onion”)

False Items: items not from list but related (“carrot”)

New Items: items not from list and unrelated (“Belgium”)

Question 26

what are the results of Cabeza et al. (2001)

Answer 26

• , Dissociation in medial temporal lobe activation
• Hippocampus activation was greater for true (old) items than new items
• But the same activation as false items
• Suggests hippocampus is involved in semantic memory (since items were semantically associated)
• Dissociation in medial temporal lobe activation
• Left parahippocampal gyrus: false items and new items produced similar activation (much less than true/old items)
• Suggests parahippocampal gyrus involved in memory for sensory information
• Lists delivered in different voices!

Question 27

what does Cabeza et al. (2001) summarise about teh brain regions which play a part in false memories

Answer 27

mixed messages from the medial temporal lobe

• Medial temporal lobe provides different types of messages when stimuli are presented in a false memory paradigm
• Anterior hippocampus suggests that false items are similar to true (old) items
• Correct in respect to semantic information

Posterior parahippocampal activity suggests that false items are similar to new items
- Correct in respect to sensory information

Question 28

explain what happened in Neuroscience of False Memories: Atkins & Reuter-Lorenz (2011)

Answer 28

an fmri study of the DRM task

Question 29

what was found in Neuroscience of False Memories: Atkins & Reuter-Lorenz (2011)

Answer 29

• Dorsolateral prefrontal cortex (DLPFC) activation associated with correct rejections of lures
• This part of the brain linked to post-retrieval source monitoring (Achim & Lepage, 2005)
• Areas showing increased activation for correct rejection of lures versus unrelated negative probes (Atkins & Reuter-Lorenz, 2011)

Question 30

what is the take home message

Answer 30

In recognition and recall, false memories can be induced using semantically related ‘foils’
Not just increased familiarity: participants believe that the item was presented (K and R responses)
False memories of real life events can be induced.
Potentially devastating impact!
Legal context highlights the importance of understanding these memories
Some indication that brain activity differs for true and false memories.
Mixed messages in medial temporal lobe depending on the type of information about an item