Lecture 8 (Memory and Forgetting) (2).ppt

Memory & Forgetting Lecture 8 Overview of Major Topics • Reconstructive Memory and Semantic Integration • Propositions, Semantic Memory and Scripts • False Memories, Eyewitness Memory and Forgotten Memories • Autobiographical Memories Combining Episodic and Semantic Memory • The normal, everyday...

Memory & Forgetting Lecture 8 Overview of Major Topics • Reconstructive Memory and Semantic Integration • Propositions, Semantic Memory and Scripts • False Memories, Eyewitness Memory and Forgotten Memories • Autobiographical Memories Combining Episodic and Semantic Memory • The normal, everyday operation of long term memory involves the continual, coordinated, cooperative processes of interaction between these two memory systems. Schacter’s (1999) Seven Sins of Memory Reconstructive Memory and Semantic Integration • Bartlett’s (1932) “War of the Ghosts” Study • Bartlett was interested in studying memory for meaningful material. • Subjects read a folk tale, and then re-told it several times. • Bartlett looked at progressive changes in what subjects remembered about the story. Constructionist Memory Research  Bartlett (1932) “The War of the Ghosts” A “foreign” story Many errors in people’s reproductions The “errors” tended to fit Western schemas Memories are reconstructed rather than veridical.  Note: This does not necessarily mean that ALL memories are reconstructive. Reproductive Versus Reconstructive Memory • Reproductive memory: A highly accurate, verbatim recording of an event. • Reconstructive Memory: Remembering by combining elements of experience with existing knowledge. • Is all memory reconstructive? Schemata • A schema is a stored framework or body of knowledge about some topic. • Bartlett used this concept to explain subject alterations when re-telling the War of the Ghosts story. • When we encounter new material, we try to relate it into existing schemas (sometimes even altering the material to make it fit). Reconstructive Effects • Sulin and Dooling (1974). • Subjects read identical stories about either: Gerald Martin or Adolf Hitler. Carol Harris or Helen Keller. • The Hitler and Keller groups’ “memory” of these stories were influenced by their knowledge of Hitler or Keller. Semantic Integration • Bransford and Franks (1971) • Subjects studied simple sentences that together told a story: • The ants were in the kitchen. • The ants ate the Jelly. • The jelly was sweet. • The jelly was on the table. Semantic Integration, Continued • At test, subjects “remembered” seeing complex sentences that captured the meaning of the simple sentences that were actually present at study: • The ants in the kitchen ate the sweet jelly on the table. • The simple sentences were integrated into one sentence that captured the story’s gist. Technical Versus Content Accuracy • Technical Accuracy: Recalling or recognizing exactly what was experienced (generally quite poor). • Content Accuracy: Recalling or recognizing the meaning or content of what was experienced (generally quite accurate). Propositions • A set of semantic nodes connected by labeled pathways, where the entire collection of concepts and relationships expresses the sentence’s meaning. Propositional versus Network Representations Elaborated Propositions • Anderson (1985). • The Hippie Touched the Debutante in the Park. Propositional Representation of the “Hippie” Sentence Semantic Cases in the “Hippie” Sentence • • • • • • The Hippie touched the debutante in the park. Relation (touch) Agent (hippie) Patient (debutante) Location (park) Time (in the past) Strengths of Propositional Theories • Propositions: Accurately reflect the meaning of the sentence. Ignore the surface form of the sentence (much like our memory system does). Have the power to represent complex sentencebased connections. Rules for Deriving Propositions 1 Find all the relational terms in the sentence. 2 Write a simple sentence for each relation. 3 Draw nodes (ovals) for each proposition. 4 Add a node to each proposition for each argument or noun in the proposition. 5 Connect arguments to the numbered oval with arrows. 6 Rearrange the network to make it neat. Are Propositions Real? • Sachs (1967) • Subjects read a text passage and were tested for a critical sentence in the passage at various time intervals. • Results: We quickly lose information about the actual verbatim string of words that we hear, but we do retain the words’ meaning. Additional Evidence • Kintsch and Bates (1977) • Gernsbacher (1985) • Kintsch (1974) Propositions and Priming (Ratcliff & McKoon, 1978) • Subjects saw sentences containing two propositions each (Example: Geese crossed the horizon as wind shuffled the clouds). • Subjects were then shown single words in a recognition task, and had to say “yes” if the word had been in one of the learned sentences and “no” otherwise. • Included several priming manipulations. Results of Ratcliff and McKoon (1978) Scripts • Large scale semantic and episodic knowledge structures that guide our interpretation and comprehension of daily experience. • Generalized memory representations of events we have experienced. • Examples: Restaurant and Classroom scripts. Script Theory Schank and Abelson (1977) Headers: Phrases or words that activate a script. • • Frames: Details about specific events within the script. • Default Value: The common, typical value that occupies a frame. False Memories • • • • • • • • blanket doze slumber snore nap peace yawn Recall the words now! • • • • • • • bed rest awake tired dream wake snooze DRM False Memory Task Deese (1959) Roediger & McDermott (1995) Did you “remember” the word “sleep?” In recognition, false memory to the lure (sleep) is often as strong as accurate memory for target items (blanket, doze). • Content versus technical accuracy? • • • • Leading Questions and Memory Distortions (Loftus & Palmer, 1974) • Subjects saw the same film of a car accident • Later, different subjects were asked: How fast were the cars going when they: smashed? collided? bumped? contacted? Loftus and Palmer, Results • Subjects estimates of speed varied with the verb they got in the question phase of the experiment. • Subjects who got the stronger verb “remembered” the cars were going faster. • Two weeks after the film: Did you see the broken glass (note: No glass was present in the original film)? Loftus & Palmer (1974) • Follow-up question: – Was there broken glass? • Smashed: ~30% yes • Contacted: ~10% yes Estimate of Vehicle Speed as a Function of Verb Use 45 Speed (MPH) • Asked: – How fast were the cars going when they ______ each other? 40 35 30 Smashed Collided Bumped Hit Contacted Possible Conclusions • Memory Impairment: A genuine change in memory of an experienced event as a function of some later event. -Versus • The Response Bias Explanation: No memory impairment– subjects use the verb to infer that the cars must have been traveling faster (or slower) than previously remembered. Source Misattribution • The inability to distinguish whether the original event or some later event was the source of the information. • Did I remember the word “sleep” because it was actually in the study list, or because I thought about the word as I looked at the study list? Misinformation Acceptance • When people accept additional information as having been part of an earlier experience without actually remembering that information. • Did I remember the car was speeding because it was, or because the police officer suggested it was? Overconfidence in Memory • Comes from two factors: • Source Memory: Memory of the exact source of the information. And • Processing Fluency: The ease with which something comes to mind. Recovered Memories of Abuse • A person remembers now that 20 years ago, someone sexually abused them. • Traumatic memory was previously repressed, but was recovered (often) under hypnosis in therapy. • Validity of recovered memories? • Empirical evidence for Freudian repression? Mechanisms of Repression • People tend to exhibit amnesia for disturbing experiences (Freud, 1915).  Anxiety-provoking experiences are repressed in order to minimize the debilitating effects of anxiety and depression.  Repressed memories are not recalled even under conditions when other experiences would be remembered  Repression is not equivalent to (active) forgetting, but is, rather, a defense mechanism. Are Repressed Memories Real? • The idea of repressed memories is consistent with recordkeeping accounts of memory deeply disturbing memories are stored and can be brought back into consciousness by a skilled psychotherapist. • The lifting of repression ?? accepted by: psychoanalysts, legal scholars and the general population  However, most cognitive psychologists question the validity of recovered memories. Real Life Consequences of Repressed Memories • George Franklin became the first person convicted solely on the basis of a recovered memory. Eileen, his daughter, claimed to have recovered memories of her father raping and killing her childhood friend 20 years earlier. • The conviction was overturned in 1995. • Melody Gavigan confronted her father with accusations that he had molested her as an infant following several psychotherapy sessions. Later SHE concluded that these memories were false. Problems with Repressed Memory Retrieval • Often no corroborating evidence.  Are anxiety laden memories harder to recall for some individuals?  Are the ‘repressed’ event and current behaviour really connected? Assessing the evidence • Amnesia appears to be more common in individuals who experienced abuse prior to adolescence – Unverified – Uncontrolled investigation  Evidence for Memory Contamination  Newspapers, films, family, friends  Inaccuracies and altered memories  Non-specifics becoming increasing specific  Empirical evidence for the creation of false memories: Spanos et. al.(1991), Loftus & Coan (1993) False Memories and Repressed Memories Empirical Investigations • False memories can easily be demonstrated in both laboratory and natural settings. They are a valid phenomena. • False memories are influenced by the interference of secondary material, and the types of questions and memory tasks employed. • Repression can also be demonstrated but explanatory hypothesis differ – repression vs. competition. • Investigations of eyewitness memory demonstrate that memory recall is positively correlated with violence (specific not peripheral detail). Conclusions on Repression • Empirical evidence supporting repression is scanty, often open to multiple interpretations • Empirical evidence to contradict repression • Some repressed memories are more than likely false memories, however, we must be cautious not to ignore all accounts of repressed memories. Autobiographical Memory • The study of one’s lifetime collection of personal memories. • Bahrick’s study on very-long-term memory of high school classmate’s names and faces. • Used six different types of memory tests. • Recognition held up nicely through the years, but recall performance was poor. Results of Bahrick’s Study Lab Versus Real World Memory • Neisser (1978) • If X is an interesting or socially significant aspect of memory, then psychologists have hardly ever studied X. • Mook (1983) • External validity is often overrated-- especially if an experiment is designed to test a theory (as many in this class are). Flashbulb Memories • Extremely accurate (seemingly), very detailed memories of particular events, especially when the events were surprising or highly unusual. • Examples: The Space Shuttle disaster. • The collapse of the Berlin Wall. • September 11, 2001?