Presentation on theme: "Key points for lecture 4 Forgetting: good or bad? How does the Deese / Roediger / McDermott (DRM) paradigm work? Which factors increase or decrease false."— Presentation transcript:
Key points for lecture 4 Forgetting: good or bad? How does the Deese / Roediger / McDermott (DRM) paradigm work? Which factors increase or decrease false memory? What are the actual underlying (cognitive) causes of false memory? Reisberg, Chapter 7.
When Memories Go Wrong What happens when your memory of an event does not correspond to what actually happened? –In what ways can our decisions get warped by an inaccurate memory? –Are we always aware when this happens?
Forgetting Is Normal! And desirable! The Case of S (Luria, 1968)
The Case of S S did not benefit a great deal from having a perfect memory. –Impaired ability to abstract general knowledge from his experiences. –Related to his inability to forget specific details of each event? –Almost the opposite of Varga-Khadems amnesic children.
Episodic vs. Semantic Memory Baddeleys Metaphor Our general knowledge is represented in a distinct semantic Memory
Episodic & Semantic Components of Autobiographical Memory Parker et al. (2006), Neurocase 12: pages (pdf available via my webpages) Case A.J. : …highly superior semantic autobiographical memory
Sources of Error in Normal Memory Forgetting. –A natural feature of our memory? Recollection and familiarity may have to trade off against one another all the time. –How might their interaction distort our memory of the past, and mislead our judgement?
The Weight of Eyewitness Evidence An estimated 77,000 people annually in the USA are charged solely on the basis of eye witness evidence. Around three quarters of English cases result in conviction due to eye witness testimony (of which half were based on a single eye witness).
Introducing Distortions into Memory Force subjects to experience very similar kinds of episodes, which become hard to discriminate from one another Manipulating the familiarity of retrieval cues
The Deese (1959) Recall Task Deese constructed his lists using word association norms. Each item in a list is a strong associate of a particular TARGET word. Deese found high levels of recall intrusions by these unpresented TARGET items.
Roediger and McDermott (1995) Modified and extended Deeses basic result. –Employing recall and recognition tasks –Use of the Remember / Know (R/K) procedure.
The Remember / Know Procedure Ask subjects to report on their experiences while recognising. –Do they Remember any episodic details? –Or do they just know the information was encountered at study?
Recognition Test List –PLACE –SWEET –TABLE –PARTY –GENERAL –MEMORY –CONSENSUS –KING –COMPUTER –TREE –FERRET –BURGLAR –BOTTLE
Roediger and McDermott (1995) Percent Recognition
Some Factors that increase or decrease DRM False Memory Increase: the number of associates presented for study Increase: the strength of association between study list items and their TARGET Decrease: (in young people) multiple study-test cycle. Decrease: the distinctiveness heuristic
Distinctiveness Heuristic Two study conditions –Words from the DRM lists –Words from the DRM lists paired with a picture False recognition was almost absent when words had been paired with pictures The ability to recollect picture information was diagnostic for studied items. –
A triple whammy! 3 Reasons for DRM False Memory (1) Implicit associative responses –subjects themselves generate the target items while studying each list. –Then experience source confusions at test (2) Familiarity of lure items –But what about the Remember responses? (3) A loss of encoding specificity
The puzzle raised by false memory Within the consensus view, how is it possible to recollect events that never took place? That is, what might cause Source errors? Familiarity-based confusions? Loss of encoding specificity?
CMF Explanations for DRM False Memory The hippocampal formation l Pattern separation failure at encoding l Pattern completion failures at retrieval l Therefore: source errors, & loss of encoding specificity The frontal lobes l Strategic control over memory l Failure to adequately focus on cues and/or monitor retrieval The entire association neocortex l Represents very similar content across a succession of episodes
Summary Judgements are most accurate when they are made on the basis of information whose source has been recollected. But if retrieval instructions allow it, judgements may be based, by default, upon potentially less accurate familiarity. –