Three Stages of Memory• Three memory stores that differ in function, capacity,and durationLong-termMemoryWorking orShort-termMemorySensoryInputSensoryMemoryAttentionEncodingRetrievalMaintenance Rehearsal
Sensory Memory• Function—holdsinformation long enoughto be processed for basicphysical characteristics• Capacity—large– can hold many items at once• Duration—very briefretention of images– .3 seconds for visual info– 2 seconds for auditory infoSensoryInputSensoryMemory
Sensory Memory• Divided into two types– iconic memory: visualinformation– echoic memory:auditory information• George Sperlingstudied iconic memorySensoryInputSensoryMemory
Sensory Memory• Sensory memory formsautomatically, withoutattention or interpretation• Attention is needed totransfer information toworking memorySensoryInputSensoryMemory
Sensory Memory• Visual sensory memory—brief memoryof an image or icon. Also called iconicmemory.• Auditory sensory memory—briefmemory of a sound or echo. Also calledechoic memory.• Auditory sensory memories may last a bitlonger than visual sensory memories.
Short-term or Working MemoryWorking orShort-termMemorySensoryInputSensoryMemoryAttention
Short-term Memory• Function—conscious processing ofinformation– where information is actively worked on• Capacity—limited (holds 7 +/- 2 items)• Duration—brief storage (about 30 seconds)Working orShort-termMemorySensoryInputSensoryMemoryAttention
Maintenance Rehearsal• Mental or verbal repetition of informationallows information to remain in workingmemory longer than the usual 30 secondsWorking orShort-termMemorySensoryInputSensoryMemoryAttentionMaintenance Rehearsal
Chunking• Grouping small bits of informationinto larger units of information– expands working memory load• Which is easier to remember?– 4 8 3 7 9 2 5 1 6– 483 792 516
Long-term Memory• Once information passes from sensory toworking memory, it can be encoded intolong-term memoryLong-termMemoryWorking orShort-termMemorySensoryInputSensoryMemoryAttentionEncodingRetrievalMaintenance Rehearsal
Long-Term Memory• Function—organizes and stores information– more passive form of storage than working memory• Unlimited capacity• Duration—thought by some to be permanentLong-termMemoryWorking orShort-termMemorySensoryInputSensoryMemoryAttentionEncodingRetrievalMaintenance Rehearsal
Long-Term Memory• Encoding—process that controls movement fromworking to long-term memory store• Retrieval—process that controls flow of informationfrom long-term to working memory storeLong-termMemoryWorking orShort-termMemorySensoryInputSensoryMemoryAttentionEncodingRetrievalMaintenance Rehearsal
Automatic Versus Effortful Encoding• Automatic processing– Unconscious encoding of information– Examples:• What did you eat for lunch today?• Was the last time you studied during the day or night?• You know the meanings of these very words you arereading. Are you actively trying to process thedefinition of the words?
Automatic Versus Effortful Encoding• Effortful processing– Requires attention and conscious effort– Examples:• Memorizing your notes for your upcomingIntroduction to Psychology exams• Repeating a phone number in your head untilyou can write it down
Types of Long-term Memory• Explicit memory—memory withawareness; information can beconsciously recollected; also calleddeclarative memory• Implicit memory—memory withoutawareness; memory that affects behaviorbut cannot consciously be recalled; alsocalled nondeclarative memory
Explicit Memory• Declarative or conscious memory• Memory consciously recalled ordeclared• Can use explicit memory todirectly respond to a question• Two subtypes of explicit memory
Explicit Memory• Episodic information—informationabout events or “episodes”• Semantic information—informationabout facts, general knowledge,school work
Episodic Memory• Memory tied to your own personalexperiences• Examples:– What month is your birthday?– Do you like to eat caramel apples?Q: Why are these explicit memories?A: Because you can actively declare youranswers to these questions
Semantic Memory• Memory not tied to personal events• General facts and definitions aboutthe world• Examples:– How many tires on a car?– What is a cloud?– What color is a banana?
Semantic MemoryQ: Why are these explicit memories?A: Because you can actively declare youranswers• Important note: Though you may havepersonal experience with these items, yourability to answer does NOT depend on tyingthe item to your past– i.e., you do not have to recall the time last week when youate a banana to say that bananas are yellow
Implicit Memory• Nondeclarative memory• Influences your thoughts orbehavior, but does not enterconsciousness• Three subtypes—we will look onlyat one (procedural)
Procedural Memory• Memory that enables you to perform specificlearned skills or habitual responses• Examples:– Riding a bike– Using the stickshift while driving– Tying your shoe lacesQ: Why are these procedural memories implicit?A: You don’t have to consciously remember the stepsinvolved in these actions to perform them– Try to explain to someone how to tie a shoelace
Culture and Early Memory• Cross-cultural research has shown howculture helps shape one’s sense of self• Research has shown that Americans’ firstmemories focused on themes of self-awareness and individual autonomy• Asians’ first memories often include otherpeople, centering on collective activities
How are memories organized?• Hierarchical organization• Associations
• Related items clustered together to formcategories• Related categories clustered together to formhigher-order categories• Remember list items better if list presented incategories– poorer recall if presented randomly• Even if list items are random, people stillorganize info in some logical patternHierarchical Organization
Semantic Network Model• Mental links between concepts– common properties provide basis for mentallink• Shorter path between two concepts =stronger association in memory• Activation of a concept startsdecremental spread of activity tonearby concepts
Review of Long-term MemoryLong-termMemoryWorking orShort-termMemorySensoryInputSensoryMemoryAttention EncodingRetrievalMaintenance Rehearsal• Retrieval transfers info from LTM to STM• Forgetting—inability to retrieve previouslyavailable information• Why do people forget?
Why Do We Forget?• Forgettingcan occurat anymemorystageRetrieval from long-term memoryDepending on interference, retrievalcues, moods, and motives, somethings get retrieved, some don’tLong-term storageSome items are altered or lostShort-term memoryA few items are both noticedand encodedSensory memoryThe senses momentarily registeramazing detail
Forgetting as Retrieval Failure• Retrieval—process of accessing stored information• Sometimes info is encoded into LTM, but we can’tretrieve itRetrieval failureleads to forgettingRetrievalXEncodingShort-termmemoryLong-termmemory
Tip-of-the-Tongue (TOT) Experience• TOT—involves the sensation ofknowing that specific information isstored in long-term memory butbeing unable to retrieve it• Can’t retrieve info that youabsolutely know is stored in yourLTM
Measures of Retrieval• Recall—test of LTM that involves retrieving memorieswithout cues; also termed free recall• Cued recall—test of LTM that involves rememberingan item of information in response to a retrieval cue• Recognition—test of LTM that involves identifyingcorrect information from a series of possible choices.• Serial position effect—tendency to remember items atthe beginning and end of a list better than items inthe middle.
Encoding Specificity– When conditions of retrieval are similar toconditions of encoding, retrieval is morelikely to be successful– You are more likely to remember things ifthe conditions under which you recall themare similar to the conditions under whichyou learned them
Encoding Specificity• Context effects—environmental cuesto recall• State dependent retrieval—physical,internal factors• Mood congruence—factors related tomood or emotions
Flashbulb MemoryThe recall of very specific images ordetails surrounding a vivid, rare, orsignificant personal event; details mayor may not be accurate (e.g., 9/11,wedding day, high school graduation)
The Forgetting CurveHermann Ebbinghausfirst began to studyforgetting by usingnonsense syllablesNonsense syllablesare three-lettercombinations thatlook like words butare meaningless(ROH, KUF)
Encoding FailuresEven though you’ve seenthousands of pennies, you’veprobably never looked at oneclosely enough to encodespecific features.
Déjà VuA brief but intense feeling ofremembering a scene or an event thatis actually being experienced for thefirst time. French for “already seen.”
Decay Theories• Memories fadeaway or decaygradually ifunused• Time playscritical role• Ability to retrieveinfo declines withtime after originalencodingAveragepercentageofinformationretained20mins1hr8hrs24hrs2d6d31dInterval between original learningof nonsense syllables andmemory test100%
Decay Theories•Biology-based theory•When new memory formed, it creates amemory trace— a change in brain structure or chemistry•If unused, normal brain metabolicprocesses erode memory trace•Theory not widely favored today
Interference Theories• “Memories interfering withmemories”• Forgetting NOT caused by merepassage of time• Caused by one memory competingwith or replacing another memory• Two types of interference
Two Types of InterferenceTypes of InterferenceRetroactiveInterferenceProactiveInterference
Retroactive Interference• When a NEW memory interferes withremembering OLD information• Example: When new phone numberinterferes with the ability to rememberold phone number
French 101Mid-termexamRetroactive InterferenceExample: Learning a new languageinterferes with ability to rememberold languageF-Study Frenchpapierlivre plumeécoleStudy Spanishpapellibro plumaescuelaretroactive interference
Proactive Interference• Opposite of retroactiveinterference• When an OLD memoryinterferes with rememberingNEW information• Example: Memories ofwhere you parked your caron campus the past weekinterferes with ability findcar today
Motivated ForgettingUndesired memory is held back fromawarenessSuppression—conscious forgettingRepression—unconscious forgetting(Freudian)
Loftus Experiment• Subjects shown video ofan accident between twocars• Some subjects asked:How fast were the carsgoing when they smashedinto each other?• Others asked: How fastwere the cars going whenthey hit each other?AccidentLeading question:“About how fast were the cars goingwhen they smashed into each other?”Memory construction
Eyewitness Testimony• Scripts—type of schema–Mental organization of events in time–Example of a classroom script: Comeinto class, sit down, talk to friends, bellrings, instructor begins to speak, takenotes, bell rings again, leave class,etc.
Eyewitness Testimony• Recall not an exact replica of original events• Recall a construction built and rebuilt fromvarious sources• Often fit memories into existing beliefs orschemas• Schema—mental representation of an object,scene, or event– Example: schema of a countryside may include greengrass, hills, farms, a barn, cows, etc.
The Misinformation EffectA memory-distortion phenomenon inwhich a person’s existing memoriescan be altered if the person isexposed to misleading information
Source Confusion• A memory distortion that occurs whenthe true source of the memory isforgotten• Can give rise to a false memory: adistorted or fabricated recollection ofsomething that did not actually occur
Memory Distortions• Memory can be distorted as peopletry to fit new info into existingschemas• Giving misleading information after anevent causes subjects to unknowinglydistort their memories to incorporatethe new misleading information
Forming False MemoriesA person can actually believe an eventoccurred by imagining the event; called“imagination inflation”
Biological Basis of MemoryKarl Lashley searched fora localized memory traceor engram.Found that maze-learningin rats was distributedthroughout the brain
Biological Basis of MemoryRichard Thompsonfound that memory forsimple classicallyconditioned responseswas localized (in thecerebellum).
New Memories in a Snail• Aplysia—asea snailused tostudy howmemoriescan changeneurons
Biological Basis of Memory• Amnesia—severe memory loss• Retrograde amnesia—inability toremember past episodic information;common after head injury; need forconsolidation• Anterograde amnesia—inability to formnew memories; related to hippocampusdamage
Gradually Losing theAbility to RememberDementia: Progressive deterioration and impairment ofmemory, reasoning, and other cognitive functionsoccurring as the result of a disease or a conditionAlzheimer’s disease (AD): A progressive diseasethat destroys the brain’s neurons, gradually impairingmemory, thinking, language, and other cognitivefunctions, resulting in the complete inability to carefor oneself; the most common form of dementia
Strategies for Boosting Memory• Focus attention• Commit the time• Space study sessions• Organize theinformation• Elaborate on thematerial• Use visual imagery• Use a mnemonicdevice• Explain it to a friend• Reduce interferencewithin a topic• Counteract the serialposition effect• Use contextual clues• Sleep on it• Forget the ginkgobiloba