copyright © 2010 pearson education canada10-1copyright © 2010 pearson education canadacopyright ©...

Copyright © 2010 Pearson Education Canada 10-1Copyright © 2010 Pearson Education Canada -1Copyright © 2010 Pearson Education Canada

MemoryMemory

Chapter 10Chapter 10

Copyright © 2010 Pearson Education Canada 10-2Copyright © 2010 Pearson Education Canada -2Copyright © 2010 Pearson Education Canada -2

Chapter OutlineChapter Outline

• Reconstructing the PastReconstructing the Past

• Memory and the Power of SuggestionMemory and the Power of Suggestion

• In Pursuit of MemoryIn Pursuit of Memory

• The Three-Box Model of MemoryThe Three-Box Model of Memory

• The Biology of MemoryThe Biology of Memory

• How We RememberHow We Remember

• Why We ForgetWhy We Forget

• Autobiographical MemoriesAutobiographical Memories

Copyright © 2010 Pearson Education Canada 10-3

Reconstructing the PastReconstructing the Past

• MemoryMemory reflects: reflects:

– The capacity to retain and retrieve informationThe capacity to retain and retrieve information

– The changes in the structures that account for The changes in the structures that account for this capacitythis capacity

– Reconstructive processesReconstructive processes

• E.g., the case of H.M. (1926-2008) and memory E.g., the case of H.M. (1926-2008) and memory impairmentimpairment


Manufacture of MemoryManufacture of Memory

• Many metaphors over time that don’t Many metaphors over time that don’t acknowledge that memory is acknowledge that memory is selectiveselective

– Bartlett’s (1932) studies and Bartlett’s (1932) studies and reconstructive reconstructive memorymemory

– Reconstruction often involves Reconstruction often involves source source misattribution:misattribution: the inability to distinguish an the inability to distinguish an actual memory of an event from information you actual memory of an event from information you learned about the event elsewherelearned about the event elsewhere


The Fading FlashbulbsThe Fading Flashbulbs

• Unusual, shocking, or tragic events may hold Unusual, shocking, or tragic events may hold a special place in memorya special place in memory

• Flashbulb memories:Flashbulb memories: characterized by characterized by surprise, illumination, and seemingly surprise, illumination, and seemingly photographic detailphotographic detail

– Events seem frozen in time and detailEvents seem frozen in time and detail

– But even flashbulb memories have errors!But even flashbulb memories have errors!


ConfabulationConfabulation

• ConfabulationConfabulation

– Confusion of an event that happened to Confusion of an event that happened to someone else with one that happened to yousomeone else with one that happened to you

– Belief that you remember something when it Belief that you remember something when it never actually happened never actually happened

– False memories can be as stable over time as False memories can be as stable over time as true onestrue ones


Conditions of ConfabulationConditions of Confabulation

• Confabulation is most likely when:Confabulation is most likely when:

1.1. You have thought, heard, or told others about You have thought, heard, or told others about the imagined event often (the imagined event often (imagination inflationimagination inflation))

2.2. The image of the event contains lots of details The image of the event contains lots of details that make it feel real that make it feel real

3.3. The event is easy to imagineThe event is easy to imagine


Memory & SuggestionMemory & Suggestion

• Eyewitness testimony is important, but not Eyewitness testimony is important, but not always reliable … always reliable …

– E.g., case of Thomas SophonowE.g., case of Thomas Sophonow

• Factors that influence eyewitness accuracy:Factors that influence eyewitness accuracy:

– Cross-race identification, the wording of Cross-race identification, the wording of questions, questions, leading questionsleading questions, misinformation, , misinformation, suggestive commentssuggestive comments


Children’s TestimonyChildren’s Testimony

• Can children be accurate eyewitnesses?Can children be accurate eyewitnesses?

– Yes, but influenced by same factors as adults, Yes, but influenced by same factors as adults, especially repeated and suggestive questioningespecially repeated and suggestive questioning

• May lead them to say and come to recall events May lead them to say and come to recall events that never happenedthat never happened

– E.g., Canadian case in Martensville, E.g., Canadian case in Martensville, Saskatchewan in 1992Saskatchewan in 1992


Children’s TestimonyChildren’s Testimony

• When asked if a visitor committed acts that had not When asked if a visitor committed acts that had not occurred, both age and type of questioning makes a big occurred, both age and type of questioning makes a big difference!difference!

• When investigators When investigators used techniques used techniques taken from real taken from real child-abuse child-abuse investigations, most investigations, most children said yeschildren said yes


In Pursuit of MemoryIn Pursuit of Memory

• Measuring how memory works generally Measuring how memory works generally evaluates two forms of memories:evaluates two forms of memories:

– Explicit memory:Explicit memory: conscious, intentional recollection conscious, intentional recollection of an event or of an item of informationof an event or of an item of information

– Implicit memory:Implicit memory: unconscious retention in memory, unconscious retention in memory, as evidenced by the effect of a previous experience as evidenced by the effect of a previous experience or encountered information on current thoughts or or encountered information on current thoughts or actions actions


Explicit MemoryExplicit Memory

• Refers to conscious, intentional recollectionRefers to conscious, intentional recollection

• Assessed using recall & recognition tasksAssessed using recall & recognition tasks

– Recall:Recall: the ability to retrieve & reproduce from the ability to retrieve & reproduce from memory previously encountered materialmemory previously encountered material

– Recognition:Recognition: the ability to identify previously the ability to identify previously encountered materialencountered material

• Recognition usually easier than recall tasksRecognition usually easier than recall tasks


Implicit MemoryImplicit Memory

• Also tested using the Also tested using the relearning method:relearning method: comparing time required to comparing time required to relearn material with initial relearn material with initial learning learning

• Common Common method is method is primingpriming where where a person is a person is exposed to exposed to information & information & later tested to later tested to see if this see if this influences influences behaviour or behaviour or performance on performance on another taskanother task


Models of MemoryModels of Memory

• Information-processing modelsInformation-processing models– Cognitive processes involve computer ideas of Cognitive processes involve computer ideas of encoding, encoding,

storing, and retrievingstoring, and retrieving information information– Information represented as concepts, propositions, Information represented as concepts, propositions,

images, or images, or cognitive schemascognitive schemas– Includes the Includes the three-box model of memorythree-box model of memory

• Parallel distributed processingParallel distributed processing– Knowledge is represented as connections among Knowledge is represented as connections among

thousands of interacting processing units, distributed in a thousands of interacting processing units, distributed in a vast network operating in parallelvast network operating in parallel


Three-Box Model of MemoryThree-Box Model of Memory

• Three separate memory systems Three separate memory systems

• Sensory, short-term (STM), long-term (LTM)Sensory, short-term (STM), long-term (LTM)


Sensory RegisterSensory Register

• Sensory registerSensory register

– A memory system that momentarily preserves A memory system that momentarily preserves extremely accurate images of sensory extremely accurate images of sensory informationinformation

– Specific to each sense (0.5 - 2 secs duration)Specific to each sense (0.5 - 2 secs duration)

– Identification of stimulus based on info in LTMIdentification of stimulus based on info in LTM

– Information not transferred quickly to STM is lostInformation not transferred quickly to STM is lost


Short-Term Memory (STM)Short-Term Memory (STM)

• Short-Term MemoryShort-Term Memory

– A limited-capacity memory system involved in A limited-capacity memory system involved in the retention of information for brief periodsthe retention of information for brief periods

– Used to hold information retrieved from LTM for Used to hold information retrieved from LTM for temporary use (referred to as temporary use (referred to as working memoryworking memory))

• Working memory:Working memory: STM + the mental processes the STM + the mental processes the control retrieval of information from LTM & interpret control retrieval of information from LTM & interpret information appropriately for given tasksinformation appropriately for given tasks


Short-Term MemoryShort-Term Memory

• Capacity of STM limited, as reflected in Miller’s Capacity of STM limited, as reflected in Miller’s magic number 7 +/- 2 unitsmagic number 7 +/- 2 units

– Enhance capacity by Enhance capacity by chunking:chunking: creating meaningful units creating meaningful units of information, often composed of smaller unitsof information, often composed of smaller units

• E.g., CBC is one chunk of informationE.g., CBC is one chunk of information

– Meaningful & emotional items will transfer quickly to Meaningful & emotional items will transfer quickly to LTM, others require more effort to transfer this materialLTM, others require more effort to transfer this material


Long-Term Memory (LTM)Long-Term Memory (LTM)

• LTM is the memory system involving long-LTM is the memory system involving long-term storage of informationterm storage of information

• How is information organized?How is information organized?

– Semantic categoriesSemantic categories• A larger grouping into which items similar in some A larger grouping into which items similar in some

characteristic can be placed (e.g., chair belongs to characteristic can be placed (e.g., chair belongs to the category furniture)the category furniture)

– Sound or lookSound or look• E.g., E.g., Tip-of-the-tongue (TOT) statesTip-of-the-tongue (TOT) states


Organization of LTMOrganization of LTM


Contents of LTMContents of LTM

• Procedural memories:Procedural memories: memories for the memories for the performance of actions or skills (“knowing how”)performance of actions or skills (“knowing how”)

• Declarative memories:Declarative memories: memories of facts, rules, memories of facts, rules, concepts, and events (“knowing that”)concepts, and events (“knowing that”)

– Semantic:Semantic: general knowledge, including facts, rules, general knowledge, including facts, rules, concepts, & propositionsconcepts, & propositions

– Episodic:Episodic: personally experienced events & the contexts personally experienced events & the contexts in which they occurredin which they occurred


Types of LTMTypes of LTM


Transferring MemoriesTransferring Memories

• Serial position effectSerial position effect– The tendency for recall of the first and last items on a The tendency for recall of the first and last items on a

list to surpass recall of items in the middle of the listlist to surpass recall of items in the middle of the list

• Primacy effect:Primacy effect: recall will recall will be best for items at be best for items at beginning of listbeginning of list

• Recency effect:Recency effect: recall will recall will be best for items at end of be best for items at end of listlist


The Biology of MemoryThe Biology of Memory

• Forming a memory involves chemical and Forming a memory involves chemical and structural changes at the level of the neuronstructural changes at the level of the neuron

– Long-term potentiation:Long-term potentiation: a long-lasting increase in the a long-lasting increase in the strength of synaptic responsivenessstrength of synaptic responsiveness

• Reflects Hebbian learning ideas; may involve glutamateReflects Hebbian learning ideas; may involve glutamate

– Linked to memory Linked to memory consolidation:consolidation: process by which the process by which the synaptic changes associated with recently stored synaptic changes associated with recently stored memories become durable and stable, causing memory memories become durable and stable, causing memory to be more reliableto be more reliable


Locating MemoriesLocating Memories

• Brain imaging and testing has demonstrated:Brain imaging and testing has demonstrated:

– Frontal lobe activity linked to STM tasksFrontal lobe activity linked to STM tasks

– Hippocampal activity during declarative LTM tasksHippocampal activity during declarative LTM tasks

– Prefrontal cortex & areas adjacent to hippocampus Prefrontal cortex & areas adjacent to hippocampus active when encoding words & picturesactive when encoding words & pictures

– Procedural memories linked to changes in cerebellumProcedural memories linked to changes in cerebellum

– Cerebral cortex involved in formation of LTMCerebral cortex involved in formation of LTM


Brain Structures & MemoryBrain Structures & Memory


Hormones & MemoryHormones & Memory

• Hormones released adrenal glands during stress & Hormones released adrenal glands during stress & emotional arousal enhance memoryemotional arousal enhance memory

– Combined effort of epinephrine and glucose may Combined effort of epinephrine and glucose may play a key role play a key role

– Research on “sweet memories”Research on “sweet memories”

• ModerateModerate levels of stress hormones optimal levels of stress hormones optimal

– Animal studies demonstrate that too much impairs Animal studies demonstrate that too much impairs memory memory


How We RememberHow We Remember

1.1. Effective encodingEffective encoding

– Automatic encoding:Automatic encoding: accurate encoding that accurate encoding that takes place automatically, without efforttakes place automatically, without effort

– Effortful encoding:Effortful encoding: to retain complex to retain complex information, you might have to select the main information, you might have to select the main points, label concepts, or associate the points, label concepts, or associate the information with personal experiences or information with personal experiences or material you already knowmaterial you already know



2.2. RehearsalRehearsal

– Maintenance rehearsal:Maintenance rehearsal: rote repetition of rote repetition of material to maintain availabilitymaterial to maintain availability

– Elaborative rehearsal:Elaborative rehearsal: association of new association of new information with already stored knowledge; information with already stored knowledge; analysis of new information to make it analysis of new information to make it memorablememorable

• Also involves Also involves deep processingdeep processing versus versus shallow shallow processing processing



3.3. MnemonicsMnemonics

– MnemonicsMnemonics are strategies and tricks for are strategies and tricks for improving memory, such as the use of verse or improving memory, such as the use of verse or a formulaa formula

– Involves active encoding strategiesInvolves active encoding strategies

– Examples:Examples:

• Rhymes: Thirty days hath September …Rhymes: Thirty days hath September …• Formulas: Every good boy deserves fudgeFormulas: Every good boy deserves fudge• Use of visual images or word associationsUse of visual images or word associations


Why We ForgetWhy We Forget

• Forgetting curvesForgetting curves– Ebbinghaus & LintonEbbinghaus & Linton



• Five mechanisms account for forgetting:Five mechanisms account for forgetting:

1.1. Decay Decay – Decay theory:Decay theory: information in memory eventually information in memory eventually

disappears if it is not accessed (applies better to short-disappears if it is not accessed (applies better to short-term than to long-term memory)term than to long-term memory)

2.2. ReplacementReplacement– New information can wipe out old informationNew information can wipe out old information– E.g., misinformation & the Stop Sign StudyE.g., misinformation & the Stop Sign Study



3.3. InterferenceInterference

– Retroactive interference:Retroactive interference: when recently learned material when recently learned material interferes with ability to interferes with ability to remember similar material remember similar material stored previouslystored previously

– Proactive interference:Proactive interference: when previously stored when previously stored material interferes with ability material interferes with ability to remember similar, more to remember similar, more recently learned materialrecently learned material



4.4. Cue-dependent memoryCue-dependent memory

– Cue-dependent forgetting:Cue-dependent forgetting: inability to retrieve inability to retrieve information stored in memory because of information stored in memory because of insufficient retrieval cuesinsufficient retrieval cues

• State-dependent memory:State-dependent memory: tendency to remember tendency to remember something when the physical/mental state during something when the physical/mental state during original experience/learning matches current stateoriginal experience/learning matches current state

• Mood-congruent memory:Mood-congruent memory: tendency to remember tendency to remember experiences that are consistent with one’s current experiences that are consistent with one’s current mood (forget those that are not)mood (forget those that are not)



5.5. AmnesiaAmnesia

– Psychogenic amnesia:Psychogenic amnesia: loss of personal identity loss of personal identity associated with psychological causes (e.g., need to associated with psychological causes (e.g., need to escape feelings of embarrassment, guilt, shame, escape feelings of embarrassment, guilt, shame, disappointment, emotional shock)disappointment, emotional shock)

– Traumatic amnesia:Traumatic amnesia: temporary memory loss involving temporary memory loss involving burying of specific traumatic events for a long period of burying of specific traumatic events for a long period of timetime

• Immune to distortion over time, occurs due to Immune to distortion over time, occurs due to repressionrepression (controversial)(controversial)


The Repression ControversyThe Repression Controversy

• RepressionRepression– In psychoanalytic theory, the selective involuntary In psychoanalytic theory, the selective involuntary

pushing of threatening or upsetting information into the pushing of threatening or upsetting information into the unconsciousunconscious

• Individuals are more likely to struggle with Individuals are more likely to struggle with forgetting traumatic eventsforgetting traumatic events

• Hard to distinguish repression from other forms of Hard to distinguish repression from other forms of forgettingforgetting

– Researchers argue against special unconscious Researchers argue against special unconscious mechanismmechanism


Autobiographical MemoryAutobiographical Memory

• Childhood amnesiaChildhood amnesia

– The inability to remember events and experiences that The inability to remember events and experiences that occurred during the first two or three years of lifeoccurred during the first two or three years of life

• Explanations for infantile amnesia:Explanations for infantile amnesia:

– Lack of sense of selfLack of sense of self– Impoverished encodingImpoverished encoding– A focus on the routineA focus on the routine– Children’s ways of thinking about the worldChildren’s ways of thinking about the world


Autobiographical MemoryAutobiographical Memory

• Memory and narrativeMemory and narrative

– NarrativesNarratives we compose simplify and make sense of our we compose simplify and make sense of our lives; profound influence on our plans, memories, love lives; profound influence on our plans, memories, love affairs, hatreds, ambitions, and dreamsaffairs, hatreds, ambitions, and dreams

– Memories reconstructed according to culture, and Memories reconstructed according to culture, and present needs, beliefs, experiencespresent needs, beliefs, experiences

– Central themes may serve as cognitive schemasCentral themes may serve as cognitive schemas

– Reminiscence bumpReminiscence bump – important transitions in life stand – important transitions in life stand out in memoryout in memory


Memory & MythMemory & Myth

• Implications of memory reconstruction in Implications of memory reconstruction in eyewitness eventseyewitness events

• Canadian cases of wrongful conviction based on Canadian cases of wrongful conviction based on mistaken memories:mistaken memories:

– Thomas SophonowThomas Sophonow– David MilgaardDavid Milgaard– Guy Paul MorinGuy Paul Morin– Steven TruscottSteven Truscott– Donald Marshall Jr.Donald Marshall Jr.

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