the sins of memory Flashcards
memory failures
- Forgetting your password or PIN versus
- Telling a joke to the person you heard it from
- Accidentally presenting someone else’s ideas as your own
* ‘Sins of commission’ as well as sins of ‘omission’ - Schater (1999)
* Huge legal implications in eyewitness testimony
Desse-Roediger-McDermott memory illusion:
- Participants study lists of words
- Strong tendency to falsely recognise critical lure as having been presented.
- Vivid memory - people even recall the critical lures
- Roediger and McDermott (1995, based on Deese, 1959)
why?
- Studied words are associated in knowledge base with the ‘critical lure’, so they activate the lure in memory
- Stored memory includes semantically related unstudied content = gist memory
- Memory is both general and specific
DRM memory illusion:
- Strong effect - lures can be recalled as often as studied items
- In amnesia, reduced false memory, so errors depend on normal hippocampal function
- Medial prefrontal cortex damage also reduces it - consistent with semantic knowledge schemas’ role in errors
- Dorsolateral prefrontal cortex damage and old age increase the illusion because intact memory control helps avoid it
Gist memory for pictures:
- For categorised pictures, about 20% false alarms on recognition test
- Also called mnemonic discrimination and is impaired in ageing and alzheimer’s
Barlett’s memory concept:
- People recalled unfamiliar stories shorter and distorted - elements changed as well as omitted.
- Bartlett’s memory schemas “the past operates as an organised mass” (1932, p.197)
- Memory distortion when to-be-remembered information does not fit our schemas
Bartlett’s methods:
- Not well controlled
- E.g., deliberate guessing
- No statistics
Brewer and Treyens (1981) - memory for objects in a graduate office:
- Objects rated by schema-expectancy
- Schema-expectancy helped recall of objects
- But more false recognition of high-schema objects in recognition memory test.
- Memory errors and distortion due to prior knowledge
- Lecture 1 - prior knowledge can support episodic memory when people process for meaning and when to-be-remembered information fits memory schemes
True versus false memories
- Can we tell the difference between true and false memories?
- Although they can be vivid, they might typically differ in quality
- E.g., if they contain more semantic gist and less perceptual info
True and false differ:
- fMRI scanning during retrieval
- Focus on subjectively vivid true vs false recollections
- Categorised pictures task that could elicit a memory based on semantic gist - e.g., “yes I saw a cat”
- Right hippocampus and early visual cortex both more activated during true recollection than false recollection
- Evidence that true recollection can be different - perhaps more detailed, and containing more sensory information
Meta-analysis:
- Meta-analysis of studies of false memory retrieval
- Several PFC regions commonly activated over studies
- Interpret most in terms of greater memory monitoring demands when memory is uncertain
- Included - bilateral ventrolateral PFC - semantic gist?
- But not all activations differed from true recognition
- And no consistent differences in hippocampus or sensory cortex
Memory bias and stereotypes:
- Allport and Postman (1947) - version of ‘telephone game’ showing racial memory bias against black character
- Kleider et al (2008) - gender stereotype errors increased with delay
Creating and modifying bias:
- Training to interpret neutral prose passages positively or negatively
- Encode ambiguous novel scenarios
- Recall of details from scenarios was biased to trained direction
- Biases can be induced and affect memory
- Biases may also be modified e.g., in depression/anxiety
Fake news and bias:
- Memory for real and fake stories just prior to Irelands May 2018 abortion referendum
- N=3140 online study
- Shown headlines + images relating to stories relating to ‘yes’ and ‘no’ campaigns
- For fake stories 48% either “I remember seeing/hearing this” or “I don’t remember seeing/hearing this but I remember it happening” (63% if include false belief)
- People 10-20% more likely to remember fake news consistent with their own views (group differences: 58% vs 38% for ‘no’ poster and 40% vs 30% for ‘yes’ poster)
Reality (source) monitoring:
- When and where? The ‘source’ of a memory.
○ Location on a screen, voice of speaker
○ When/ where you met someone
○ Where you put your keys
○ Imagined vs. real experience (reality monitoring)
○ The “ability to specify contextual information surrounding memory traces” (so source ~= context)- Not just recollecting context, but evaluating what is remembered – this requires control
‘Content borrowing’:
- How can a false memory have vivid perceptual details?
- False recognitions include actual physical features (colour, shape) of similar seen objects (Lyle & Johnson, 2006)
- Thinking aloud in DRM task (Lampinen et al., 2006)
- While studying word SUGAR: “It is fattening, but it is good.”
- While falsely recognising SWEET: “Sweet—old, and remember, cause I remember liking sweets but thinking they are gonna make me fat.”
- Content borrowing from true memories
Cryptomnesia:
- Unconscious plagiarism as a reality monitoring error (Gingerich and Sullivan, 2013)
- E.g., did you tell your idea to someone or did they tell it to you?
- At university, take stops to avoid e.g., don’t copy-paste from articles into your notes: paraphrase instead
‘Imagination inflation’:
- But surely false memories of whole events don’t occur?
- 1 ½ minute story from Elizabeth Loftus (link on Canvas)
- Everyday errors e.g. answering email versus thinking about it
- Imagining has a larger effect than just reading about something - and this applies to both common, feasible events and unfeasible events (Mazzoni & Memon, 2003; see Schacter et al., 2011)
- We have vivid imaginations!
In the field - complex errors:
- Distortion due to a memory schema can often be exacerbated by misattribution i.e. control failure
- E.g. clinical psychologists vs. students read case study vignettes, coherent vs. incoherent with prior knowledge
- Experts recalled more detail AND falsely recalled more details that had NOT been present!
- Particularly where schema and reality conflicted
- (NB groups differed in age… potentially serious confound!
- More than one mechanism even in lab-based DRM and other gist memory tasks
In the field - the cognitive interview:
- Stage 1: Reinstate the context (lecture 2)
- Stage 2: Recall events in reverse order
- Stage 3: Report everything
- Stage 4: Describe events from someone else’s perspective
- Stage 2 attempts to reduce schema use, Stage 3 to maximise memory monitoring and to cue further recall (along with Stage 4).
In the field - misinformation effect:
- Strong influence of post-event questioning on memory – potential for misleading information
- Loftus & Palmer (1974) car crash study
- Information introduced in questions about an event is incorporated as part of memory for original event
- Can be accounted for well by Multiple Memory Trace Theory which also addresses temporal gradient in amnesia
In the field - eyewitness testimony:
- About 75% of wrongful convictions in USA involve eyewitness errors https://innocenceproject.org/
- DNA evidence for wrongful convictions
- “Like trace evidence, eyewitness evidence can be contaminated, lost, destroyed or otherwise made to produce results that can lead to an incorrect reconstruction of the crime“ – Gary Wells
- Police questioning is critical and can change memory!
Bartlett’s (1932) war of the ghosts:
- Were schemas the only cause of distortion here?
- Memory was tested after 15 min
- Then randomly on the campus after weeks, months or years
- Begram and Roediger (1999) - replication and extension of Bartlett’s (1932) main findings for short stories
- at a 15 minute memory test, major distortions were found in about a thrid of all recalled information
Bartlett’s 2
- major distortions were an increasing proprtion of memories with repeated retrieval
- control group showed less distorted as well as less accurate recall in absolute terms - although don’t report proportion
- early test is a ‘double-edgerd sword’
Other evidence for more distortion after repeated tests:
- Graesser et al. (1980) - how can recalled text become distorted by prior knowledge?
- Chance of recalling a text item that was studied
- Probability of freely generating it when nothing studied
- Not correlated after 30 min
- After 1 week, r = 0.45 (20% of variance)
- BUT: is this representative of ‘real-life’ memory?
Students’ event memory:
- Wynn & Logie (1998) tested students’ memories for their first week at university every few weeks
- Accurate & stable over a year despite initial memory test
- AND: accuracy verified by lecturers’/ porters’ notes at time
- BUT: the initial memory test was not for 2-3 weeks
- Memory distortion may be less common in ‘naturalistic conditions’
- Consistent with proposed role of schemas as these memories may fit a schema well
Unconscious plagiarism again:
- Discussing your own and other people’s ideas may make them harder to tell them apart
- People made up novel uses for objects (ideas) and experimenter contributed additional uses (Stark & Perfect 2006)
- Elaboration on all the ideas boosted later recall
- BUT participants more likely to recall all ideas as their own!
- i.e., memory updating with memory ‘blending’
- NOTE this goes beyond content borrowing because there is an interim memory test after initial encoding