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Chapter 08: Errors in Long-­‐Term Memory 1 Do you remember where you were/what you were doing when you first heard about September 11th? Flashbulb Memories 2 Some QuesGons to Consider •  What kinds of events from their lives are people most likely to remember? •  Is there something special about memory for extraordinary events like the 9/11 terrorist aPacks? •  What properGes of the memory system make it both highly funcGonal and also prone to error? –  Is there an efficiency/accuracy trade-­‐off? •  Why is eyewitness tesGmony oSen cited as the cause of wrongful convicGons? 3 1
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Autobiographical Memory (AM) •  Recollected events that belong to a person s past (episodic memory) •  Mental Gme travel (Tulving) •  MulGdimensional –  Rich in detail –  SpaGal, emoGonal, and sensory components 4 Autobiographical Memory •  Cabeza and coworkers (2004) –  Compared brain acGvity (fMRI) caused by autobiographical memory and laboratory memory –  ParGcipants viewed •  Photographs they took (A-­‐photos) •  Photographs taken by someone else (L-­‐photos) 5 Autobiographical Memory •  Cabeza and coworkers (2004) What is the difference between seeing a photo of something you’ve seen in person versus someone else seeing an idenGcal photo? CogniGve difference? Psychological difference? 6 2
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Autobiographical Memory •  Both types of photos acGvated brain structures associated with –  Episodic memory –  Processing scenes •  A-­‐photos also acGvated brain structures associated with –  Processing info about the self –  Memory for visual space –  Mental Gme travel memory •  Such a distributed representaGon in the brain suggests these are very rich memories!!! 7 (a) fMRI response of an area in the parietal cortex showing areas acGvated by both the A-­‐photos and the L-­‐photos during the memory test. The graph on the right indicates that acGvaGon was the same for A-­‐photos and L-­‐photos. Episodic memory; Scene processing (b) Areas in the parahippocampal gyrus that were acGvated by the A-­‐photos and the L-­‐photos. The graph indicates that in this area of the brain, acGvaGon was greater for the A-­‐photos. Autobiographical; SpaGal informaGon 8 Memory Over the Lifespan •  What events are remembered well? –  Significant events in a person s life –  Highly emoGonal events –  TransiGon points 9 3
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Reminiscence Bump •  ParGcipants over the age of 40 were asked to recall events in their lives •  Memory is high for recent events and for events that occurred in adolescence and early adulthood (between 10 and 30 years of age) 10 Robert Schrauf Penn State U. •  Percentage of memories from different ages, recalled by a 55-­‐year-­‐old, showing the reminiscence bump. •
(from Journal of Memory and Language, 39, R.W. Schrauf & D.C. Rubin, Bilingual Autobiographical Memory in Older Adult Immigrants: A Test of CogniGve ExplanaGons of the Reminiscence Bump and the LinguisGc Encoding of Memories, pp. 437-­‐457, Fig. 1.) 11 Reminiscence Bump •  Hypotheses about the reminiscence bump 12 4
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Reminiscence Bump •  Self-­‐image hypothesis –  Memory is enhanced for events that occur as a person s self-­‐image or life idenGty is being formed –  People assume idenGGes during adolescence and young adulthood •  Many transiGons occur between ages 10 and 30 13 Reminiscence Bump •  Cogni;ve hypothesis –  Encoding is bePer during periods of rapid change that are followed by stability –  Evidence from those who immigrated to the US aSer young adulthood indicates reminiscence bump is shiSed 14 •  The reminiscence bump for people who emigrated at age 34 to 35 is shiSed toward older ages, compared to the bump for people who emigrated between the ages of 20 to 24. •
(from Journal of Memory and Language, 39, R.W. Schrauf & D.C. Rubin, Bilingual Autobiographical Memory in Older Adult Immigrants: A Test of CogniGve ExplanaGons of the Reminiscence Bump and the LinguisGc Encoding of Memories, pp. 437-­‐457, Fig. 2 15 5
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Reminiscence Bump •  Cultural life-­‐script hypothesis •  Each person has –  A personal life story –  An understanding of culturally expected events •  Personal events are easier to recall when they fit the cultural life script –  What is a cultural life script? •  When did you get your first car? •  Have sex? •  Vote? 16 Memory for EmoGonal SGmuli •  EmoGonal events are remembered more easily and vividly •  EmoGon improves memory, becomes greater with Gme (may enhance consolidaGon) •  Brain acGvity: amygdala •  It is important to remember that memory for emoGonal content can be enhanced, but the confidence you have in that memory is also enhanced. Why can this be a problem? 17 Flashbulb Memories •  Memory for circumstances surrounding shocking, highly charged important events (not the events themselves) –  9/11/01 –  Kennedy assassinaGon –  Challenger explosion •  Where you were, and what you were doing? 18 6
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Flashbulb Memories •  Highly emoGonal •  Vivid •  Very detailed •  People report that flashbulb memories have these qualiGes (Brown & Kulik, 1977), but do they really? 19 Flashbulb Memories •  Newer results suggest that these memories can be inaccurate or lacking in detail... –  even though parGcipants report that they are very confident and that the memories seem very vivid. Talarico & Rubin (2003) “Memory itself is an internal rumour.”
-­‐George Santayana 20 Results of Talarico and Rubin s (2003) flashbulb memory experiment.
(a) The decrease in the number of details remembered was similar for memories of 9/11 and for memories of an everyday event. (b) ParGcipants belief that their memory was accurate remained high for 9/11, but decreased for memories of the everyday event. (Talarico & Rubin, Psychological Science) 21 7
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Flashbulb Memories •  Narra;ve rehearsal hypothesis –  Repeated viewing/hearing of event •  TV, talking with others •  Could introduce errors in own memory 22 The ConstrucGve Nature of Memory •  Memory = What actually happened + person s knowledge, experiences, and expectaGons. •  Memory is not a frozen image in the brain, even at the chemical level, memories are dynamic. –  Encoding, consolidaGon, reconsolidaGon. 23 24 8
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25 The ConstrucGve Nature of Memory •  BartleP s war of the ghosts experiment –  ParGcipants aPempted to remember a story from a different culture –  Repeated reproducGon •  Results –  Over Gme, reproducGon became shorter, contained omissions and inaccuracies. –  Changed to make the story more consistent with their own culture. 26 One night two young men from Egulac went down to the river to hunt seals, and while they were there it became foggy and calm. Then they heard war cries, and they thought: "Maybe this is a war party". They escaped to the shore and hid behind a log. Now canoes came up, and they heard the noise of paddles, and saw one canoe coming up to them. There were five men in the canoe, and they said: "What do you think? We wish to take you along. We are going up the river to make war on the people". One of the young men said: "I have no arrows". "Arrows are in the canoe", they said. "I will not go along. I might be killed. My relaGves do not know where I have gone. But you", he said, turning to the other, "may go with them." So one of the young men went, but the other returned home. And the warriors went on up the river to a town on the other side of Kalama. The people came down to the water, and they began to fight, and many were killed. But presently the young man heard one of the warriors say: "Quick, let us go home; that Indian has been hit". Now he thought: "Oh, they are ghosts". He did not feel sick, but they said he had been shot. So the canoes went back to Egulac, and the young man went ashore to his house and made a fire. And he told everybody and said: "Behold I accompanied the ghosts, and we went to fight. Many of our fellows were killed, and many of those who aPacked us were killed. They said I was hit, and I did not feel sick."
He told it all, and then he became quiet. When the sun rose he fell down. Something black came out of his mouth. His face became contorted. The people jumped up and cried. He was dead. 27 9
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ReproducGon number 10 •  The War of this Ghosts: •  Two Indians were out fishing for seals in the Bay of Manpapan, when along came five other Indians in a war-­‐canoe. They were going fighGng. •  "Come with us," said the five to the two, "and fight." •  "I cannot come," was the answer of the one, "for I have an old mother at home who is dependent upon me." The other also said he could not come, because he had no arms. "That is no difficulty" the others replied, "for we have plenty in the canoe with us"; so he got into the canoe and went with them. •  In a fight soon aSerwards this Indian received a mortal wound. Finding that his hour was come, he cried out that he was about to die. "Nonsense," said one of the others, "you will not die." But he did. 28 BartleP s Analysis of the Changes •  The story became shorter and more coherent •  No trace of an odd, or supernatural element is leS: we have a perfectly straighrorward story of a fight and a death. •  Achieved by: –  Omissions: ghosts omiPed early; the wound became a maPer of flesh, not spirit –  RaGonalizaGon: growing coherence among parts –  TransformaGon of details into more familiar and convenGonal examples –  Changing order of events 29 Source Monitoring •  Source memory: process of determining origins of our memories (perceptual details, emoGons, thoughts) –  Did you hear about 9/11 from a person or TV? •  Source monitoring error: misidenGfying source of memory –  Also called source misaPribuGons 30 10
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•  Design of Jacoby et al. s (1989) becoming famous overnight experiment. old 31 Source Monitoring •  Jacoby et al. (1989) •  ASer 24 hours, some old non-­‐famous names were misidenGfied as famous •  ExplanaGon: some non-­‐famous names were familiar, and the parGcipants misaPributed the source of the familiarity –  Failed to idenGfy the source as the non-­‐famous list from the day before; the misaPribuGon was they mistakenly thought the familiar names were famous 32 Making Inferences •  Memory can be influenced by inferences that people make based on their experiences and knowledge •  Memory oSen includes informaGon that is implied by or is consistent with the to-­‐be-­‐
remembered informaGon but was not explicitly stated –  PragmaGc inferences: inferences made based on knowledge gained through experience “the baby stayed awake all night” -­‐-­‐> “the baby cried all night” actually happened your memory 33 11
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Bransford and Johnson’s (1973) experiment that tested people’s memory for the wording of acGon statements. If they read about pounding a nail (experimental group), their incorrect memory inferred that he had been using a hammer (vs “looking for a nail” [control group]). •  More errors were made by the experimental group because they idenGfied more sentences as being originally presented, even though they were not. 34 Schemas and Scripts •  Schema: knowledge about what is involved in a parGcular experience –  Post office, ball game, classroom •  Script: concepGon of sequence of acGons that occur during a parGcular experience –  Going to a restaurant; to the denGst 35 Schemas and Scripts •  Schemas and scripts influence memory –  Memory can include informaGon not actually experienced but inferred because it is expected and consistent with the schema –  Office waiGng room: books not present but menGoned in memory task (Brewer & Treyens, 1981) –  The construcGve nature of memory can lead to errors or false memories 36 12
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ConstrucGon of Memories •  Advantages –  Allows us to fill in the blanks –  CogniGon is creaGve •  Understand language •  Solve problems •  Make decisions 37 ConstrucGon of Memories •  Disadvantages –  SomeGmes we make errors –  SomeGmes we misaPribute the source of informaGon •  Was it actually presented, or did we infer it? 38 Power of SuggesGon •  MisinformaGon effect: misleading informaGon presented aSer a person witnesses an event can change how that person describes the event later –  Misleading postevent informaGon (MPI) 39 13
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Power of SuggesGon •  LoSus and coworkers (1975) Elizabeth LoSus UC Irvine –  See slides of traffic accident with stop sign –  Introduce MPI: yield sign –  ParGcipants remember what they heard (yield sign) not what they saw (stop sign) 40 Power of SuggesGon •  LoSus and Palmer (1974) –  Hear smashed or hit in descripGon of car accident –  Those hearing smashed said the cars were going much faster than those who heard hit 41 Power of SuggesGon •  Hypotheses about the misinformaGon effect 42 14
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Power of SuggesGon •  Lindsey (1990) –  Heard a story; two days later again with some details changed –  Told to ignore changes –  Same voice for both stories created source monitoring errors –  Changing voice (male to female) did not create as many errors 43 Errors in Eyewitness TesGmony •  TesGmony by an eyewitness to a crime about what he or she saw during the crime •  One of the most convincing types of evidence to a jury –  Assume that people see and remember accurately •  But, like other memory, eyewitness tesGmony can be inaccurate –  Mistaken idenGty –  ConstrucGve nature of memory 44 Errors in Eyewitness TesGmony •  Wells & Bradfield (1998) –  ParGcipants view security videotape with gunman in view for 8 seconds –  Everyone idenGfied someone as the gunman from photographs aSerwards –  The actual gunman s picture was not presented 45 15
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Errors in Eyewitness TesGmony 1.  Errors due to arousal 2.  Errors due to familiarity 3.  Errors due to suggesGon 46 Errors in Eyewitness TesGmony •  Errors due to aPenGon and arousal –  Low: aPend to irrelevant informaGon –  High: focus too narrowly –  Moderate: best for being aware of relevant informaGon 47 •  Results of Stanny and Johnson s (2000) weapons-­‐focus experiment. Presence of a weapon that was fired is associated with a decrease in memory about the perpetrator, the vicGm, and the weapon. 48 16
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Errors in Eyewitness TesGmony •  Errors due to familiarity –  Source monitoring 49 (a) Design of Ross et al. s (1994) experiment on the effect of familiarity on eyewitness tesGmony. (b) When the actual robber was not in the photospread, the male teacher was erroneously idenGfied as the robber 60 percent of the Gme. (c)  When the actual robber was in the photospread, the male teacher was erroneously idenGfied less than 20 percent of the Gme. 50 Errors in Eyewitness TesGmony •  Errors due to suggesGon –  SuggesGve quesGoning •  MisinformaGon effect –  Confirming feedback 51 17
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•  Wells and Bradfield s (1998) Good, you idenGfied the suspect experiment. •  The type of feedback from the experimenter influenced the parGcipants confidence in their idenGficaGon, with confirming feedback resulGng in the highest confidence. 52 7 Deadly Sins •  The Seven Sins of Memory: How the Mind Forgets and Remembers. –  Transience –  Absent Mindedness –  Blocking –  Bias –  MisaPribuGon –  SuggesGbility –  Persistence Daniel Schacter Harvard University 53 18