3Modal Model of Memory Atkinson & Shiffrin (1968) RehearsalInputSensoryMemoryShort-termMemoryLong-termMemoryOutputThree stages of memoryInput, Output, Rehearsal (a control process)
4Modal Model Structural Features of the Model Sensory memory: initial stage, holds info for seconds/fractions of seconds. Large capacity.Short-term Memory (STM): holds 5-7 items for seconds. Control processes can extend this.Long-term Memory (LTM): holds a large amount of information for years, even decadesControl processes: active memory strategies controlled by individual (example: rehearsal)
5Control Processes Some control processes maintain info in STS Rehearsal (repeat the items over and over)Chunking (make connections between items)VisualizationSome control processes affect transfer between STS and LTS (storage and retrieval)MemorizationRecallYou can only process information in STS
7Sensory Memory Sensory memory is very short Allows you to see the “trail” of a sparklerAllows you to see movies (flipbook, tachistoscope)Auditory Sensory Memory is also calledEchoVisual Sensory Memory is also calledPersistence of visionIconic Memory / Visual Icon
8Sperling (1960): Iconic Memory Whole report conditionX M L TA F N BC D Z PXF DZ C
9Sperling (1960): Iconic Memory Partial report conditionX M L TA F N BC D Z PX ML T
10Sperling (1960): Iconic Memory What’s the point?Sperling was studying visual sensory memoryBefore his study, people thought that visual sensory memory could only hold 4-5 items (full report cond)The other conditions in his study showed thatIt’s true that people can only report 4-5 items before memory decays (or fades away)BUT sensory memory actually encodes the whole sceneConclusion: Sensory Memory has a large capacity, but fast decay
11Sperling (1960): Iconic Memory Partial report delayedconditionX M L TA F N BC D Z PM
12Sperling (1960): Iconic Memory Summary of conditionsWhole report conditionAll 12 letters flash on/off -> 1s. delay -> report anyPartial report conditionAll 12 letters flash on/off -> auditory cue to row -> report just that rowPartial report delayed conditionAll 12 letters flash on/off -> 1s. Delay -> auditory cue to row -> report just that row
13Sperling (1960): Timing of Decay What’s the point?Sperling wanted to get a clearer picture of just how fast sensory information decaysStronger support of his hypothesis that sensory memory has large capacity and fast decayConclusion: Within just 1 second, most of sensory memory decays, leaving only what was moved to STS via attention.
14Moray, Bates & Barnett (1965) Sternberg looked at visual memory, Moray, Bates & Barnett were interested in echoic memory (auditory sensory memory)Same task for audio domain“four-eared listening”Similar effects (advantage for partial reporting)Work after that showedEchoic memory has larger capacity and slower decay than visual iconic memory
15Modalities of Sensory Memory Modality: the “channel” (Broadbent) that different inputs come in throughAuditory, visual, tactile, etc.Sensory memory is modality specificSaying “ba, ba, ba” while receiving auditory input messes up echoic, but not iconic memoryA visual mask messes up visual memory, but not auditory memoryMask: for control in experiments (as in demo)
19Sensory Memory NowIn Sternberg’s day, this evidence supported the Modal Model (which has since been replaced)Sensory memory is still important and seems to be separate from other forms of memoryStill thought to have large capacity and fast decayThought to be important forCollecting inputHolding input during initial processingFilling in “blanks” (movies, static, etc.)
21Modal Model of Memory Atkinson & Shiffrin (1968) RehearsalInputSensoryMemoryShort-termMemoryLong-termMemoryOutputThree stages of memoryInput, Output, Rehearsal (a control process)
22Short-Term Memory Short-term memory allows you to: Understand sentencesDo arithmeticDial a phone numberNavigate from one place to anotherKnow where we are and what we’re doing right nowMemory for current tasks, last few minutesMomento: main character had STM, not LTMClive Wearing: Real-world case in book
23Issues with STM Just as with Sensory Memory, two important issues are Duration (how long things stay in memory)Capacity (how many things fit in memory at a time)Studying Short-Term-Memory is complicated because people use control processes a lotRehearsal seems to extend durationChunking seems to extend capacity
24Duration of Short-term Memory Brown (1958) / Peterson & Peterson (1959)Same studies at the same time, same resultsStep 1: three letters + one number givenStep 2: count backward from numberStep 3: 3-18 s. delay (while counting backward)Step 4: recall three letters
25Duration of Short-term Memory Brown (1958) / Peterson & Peterson (1959)Same studies at the same time, same resultsPercentRecalledFIRST TRIALONLY318Delay
26Duration of Short-term Memory Brown (1958) / Peterson & Peterson (1959)Same studies at the same time, same resultsTHIRD TRIALONLYPercentRecalled318Delay
27Duration of Short-term Memory Brown (1958) / Peterson & Peterson (1959)Same studies at the same time, same resultsMANYTRIALSLATERPercentRecalled318Delay
28Duration of Short-term Memory Brown (1958) / Peterson & Peterson (1959)Same studies at the same time, same resultsAVERAGEOVER ALLTRIALSPercentRecalled318Delay
29Duration of Short-term Memory The studies by Brown and Peterson & Peterson show that the percentage of letters recalled decreases with longer delays, BUT this pattern interacts with where in the series of trials the individual trail occursRecall of letters after long delays decreases as the series of trials gets longer
30Duration of Short-term Memory What’s the point?Peterson & Peterson / Brown were interested in decay of short term memoryIt turns out, their studies demonstrate that another type of forgetting that happens in STM: proactive interferenceWhat is already in STM affects ability to add new thingsLarger point is that forgetting in STM occurs through both decay and interference (proactive and other types too) – effective duration is 15-20s.
31Capacity of Short-term Memory Capacities can vary from person-to-person, measured by digit spanGet out some paper and something to write with, we’re going to calculate your digit span
32Capacity of Short-term Memory Directions: Make sure you are running the next slides in presentation mode. You will see a list of single-digit numbers. Remember them. When you see “go” (but not before), write them down from memory, in order. When you are done writing, click to get the next set of digits.
33Capacity of Short-term Memory GO!GO!GO!GO!GO!GO!GO!
34Capacity of Short-term Memory How many digits were in the longest row that you got completely right?That’s your digit span.
35Capacity of Short-term Memory “My problem is that I have been persecuted by an integer. For seven years this number has followed me around, has intruded in my most private data, and has assaulted me from the pages of our most public journals. This number assumes a variety of disguises, being sometimes a little larger and sometimes a little smaller than usual, but never changing so much as to be unrecognizable…..
36Capacity of Short-term Memory …. The persistence with which this number plagues me is far more than a random accident. There is, to quote a famous senator, a design behind it, some pattern governing its appearances. Either there really is something unusual about this number or else I am suffering from delusions of persecution.”George Miller (1956)The Magical Number 7 (plus or minus 2)
37Capacity of Short-term Memory Miller (1956): People can remember 7±2 ….DigitsWordsNumbers (with multiple digits)PhrasesWe can remember more if it’s organizedChunking is combining smaller units into larger meaningful units, to improve capacity
38ChunkingChunking involves using Long-term memories to organize information in Short-term memoryEriccson and coworkers (1980)College student had digit-span of 79 after trainingChunked digits into meaningful times for running, a sport he was familiar withChase and Simon (1973)Chess players chunk information based on meaningful points within a game of chess
39Chunking Chase & Simon (1973) Meaningful Arrangements Random CorrectPiecePlacementsMasterBeginnerMasterBeginner
40Chunking & Information Coding What’s the point of all these chunking studies?Capacity is related to how information is representedRecall our last discussion of how information is represented, during “Cognition and the Brain”Specificity coding vs. Distributed codingDealt with how information is represented by neurons’ firing ratesThis is called a physiological approach to codingWe can also take a mental approach to coding
41Information Coding Mental approach to coding Three Types of Coding More abstract than physiological approachDeals with how things are represented in the mind / thoughtsThree Types of CodingAuditory Coding – represented as a soundVisual Coding – represented as an imageSemantic Coding –represented through meaning
42Auditory Coding Conrad (1964) Participants saw target letters (quickly flashed)Then they wrote them downMistakes were madeNot likely to replace with something that looked like the target (E for F)Likely to replace with something that SOUNDED like the target (E for B)Suggests that letters are represented by sound information (auditory coding)
43Semantic Coding Wickens and Coworkers (1976) Participants divided into groupsGroups heard lists with different meanings (fruits, professions, meats, etc.)Proactive Iterferecen for same list-TYPE repeatedCategory switch caused release from proactive interferenceEffect was larger for categories that were less similarEvidence for semantic (meaning) coding
44Short-term Memory Today The Modal Model had a nice clean vision of Short-term MemoryAll-purpose store with 15-20s duration and capacity of 7±2Simply holds informationHow information is coded affects how much information fits in STM, but not much elseThis view of STM turned out to be too simple, so it has been replaced with working memory
48Comparing Memory Models Short-term Memory (Attkinson & Shiffrin)Single component for all types of infoMainly used for holding information for a short timeWorking Memory (Baddeley & Hitch)Three components:Central ExecutiveVisuospatial SketchpadPhonological LoopUsed for manipulation of information during complex cognition
49Components of Working Memory Phonological LoopHolds verbal and auditory informationCoding or source can determine whether it’s verbal/auditory information or notVisuospatial Sketch PadHolds visual and spatial informationCentral ExecutivePulls info from long-term memory, coordinates other components, directs and maintains attention…
50A component of working memory Phonological LoopA component of working memory
51Phonological LoopThe phonological loop holds verbal and auditory information (for longer than the echo)Sources of experimental support for a component specialized for LanguagePhonological similarity effectWord-length effectArticulatory suppression
52Phonological Similarity Effect The basic effect: words that sound similar are confused by peopleWe saw that earlier today when we discussed Auditory Coding: Condrad’s study with lettersAnother example is the Coglab “Phonological Similarity” (which you can get extra credit for doing)
53Phonological Similarity Effect Experiment designHalf of the time the letters were similar and half of the time they weren’tHalf of the time you had to speak (recite numbers 1-4 in order) and half of the time you were to be quietSpeaking in this experiment is called articulatory suppression (which we’ll come back to)The two factors were independent
54Phonological Similarity Effect The U-shape doesn’t matter for nowHow do similar and dissimilar compare to each other for the quiet trials?How does this support the phonological similarity effect?
55Phonological Similarity Effect What was the point of the Phonological Similarity Effect experiment?Demonstrated the phonological similarity effect (people confuse letters that sound similar)Key point: even though information was presented visually, people converted it to auditoryAs we’ll see later, it also showed that the phonological loop is necessary for the conversion (not just holding info)
56Phonological LoopThe phonological loop holds verbal and auditory information (for longer than the echo)Sources of experimental support for a component specialized for LanguagePhonological similarity effectWord-length effectArticulatory suppression
57Word-Length EffectThe basic effect: When memorizing words, you can remember fewer words if the words are longHere’s another demo…. Just do what you did earlier for the digit span test. When you see the words try to remember them. Then, when you see “go” (but not before) write down the words you can remember. It can be any order this time. Then click to go on.
59Word-Length EffectThe basic effect: When memorizing words, you can remember fewer words if the words are longThat was a demo of a real experiment …. People remembered more of the short words than long words (Baddeley & Coworkers, 1984)American children have a longer digit span than Welsh children (Ellis & Hennelly, 1980)Because welsh numbers take longer to pronounce!Number of words you can say in seconds is likely to be your digit span
60Phonological LoopThe phonological loop holds verbal and auditory information (for longer than the echo)Sources of experimental support for a component specialized for LanguagePhonological similarity effectWord-length effectArticulatory suppression
61Articulatory Suppression The basic finding: if you speak while memorizing (which keeps the phonological loop busy) you get worse at remembering, AND the other two effects disappearCoglab “Phonological Similarity Effect” illustrates bothRemember: You can get extra credit for doing it
62Articulatory Suppression Which is less accurate on average, quiet or suppression (circles or squares) ?Is the phonological similarity effect (difference btwn black & white) stronger for quiet or suppression (circles or squares)?
63Articulatory Suppression The basic finding: if you speak while memorizing (which keeps the phonological loop busy) you get worse at remembering, AND the other two effects disappearPerformance worse in suppression conditionPhonological effect weaker in suppression conditionSimilar findings regarding the word length effectWhat is going on in these situations? Why does this support the concept of a phonological loop?
64Visuospatial Sketch Pad Another component of working memory
69Visuospatial Sketch Pad Brooks (1968) – the sentence experimentMemorize a sentenceIndicate whether each word is / is not a nounCondition 1: indicate by speakingCondition 2: indicate by pointingResults: pointing was easier than speaking for the participantsExplanation: Phonological loop was busy processing the sentence, but sketch pad was free
70Visuospatial Sketch Pad FBrooks (1968) – the “F” demoMemorize a shape (in this case an F)Indicate whether each corner is an “inside corner” or an “outside corner”Condition 1: Indicate by speakingCondition 2: Indicate by pointing
72Visuospatial Sketch Pad FBrooks (1968) – the “F” demoMemorize a shape (in this case an F)Indicate whether each corner is an “inside corner” or an “outside corner”Condition 1: Indicate by speakingCondition 2: Indicate by pointingResults: Speaking is easier than pointing (the OPPOSITE of what happened before)Explanation: Sketch Pad was busy with image, but phonological loop was free
73Visuospatial Sketch Pad What is the point of these studies?Tasks are easier when the information being held in mind and the operation being performed on it involve different types of short-term memoryVerbal / PhonologicalVisual / SpatialThat means that the two types of short-term memory are somewhat independentAt the least, separate capacities
74Another component of working memory Central ExecutiveAnother component of working memory
75Central ExecutiveThe Central Executive does the “work” of working memoryCoordinating sketchpad and phonological loopPerforming calculationsDirecting and maintaining attentionA lot of what we learned about in the attention topic is part of what the central executive doesSample source of evidence: central executive’s ability to suppress is correlated with memory
76Central Executive Gazzaley and coworkers (2005) Compared two versions of the task“face-relevant”: Remember faces, ignore scenes (test: faces)“passive”: Just watch pictures (test: arrow right/left)
78Central Executive Gazzaley and coworkers (2005) Compared two versions of the task“face-relevant”: Remember faces, ignore scenes (test: faces)“passive”: Just watch pictures (test: arrow right/left)Measures:Accuracy at remembering facesBrain activity in areas used for perceiving scenesGood suppressors: less activity in scene areas (good at ignoring)Poor suppressors: more activity in scene areas (poor at ignoring)Results: good suppressors remembered more faces
80Working Memory Baddeley (2000) Remember the other components!Episodic BufferInputSensoryMemoryCentralExecutiveLong-termKnowledgePhonologal LoopVisuospatial Sketchpad
81Working Memory Now The model successfully explains a lot of data Still a useful model that is used by manyThere is a newer one (Cowan) but details are beyond this classStill changing, though….Baddeley was frustrated that certain things didn’t seem to “fit” (effect sizes larger or smaller, etc)Episodic buffer has been added as a 5th component
83What’s this Episodic Buffer? The episodic buffer is a “backup” that talks to the central executive and long-term memoryGreater duration than loop & sketch padGreater capacity than loop & sketch padVery vague, still needs to be testedThe point is that models are constantly being refined and modified to account for new results
87Working Memory and the Brain Prefrontal cortex involved in working memoryGets inputs from the sensory areasGets inputs from areas involved in actionConnected to areas involved in long-term memoryPhysiological evidenceDelayed-response task in monkeysSingle-cell recording in monkeysBrain imaging evidence
88Working Memory and the Brain Physiological evidence based on similirities between monkey and human brainDelayed-response: Monkeys can remember a location over a delay. When monkeys have PFC removed, they can’t do that very well any more.Funahashi and coworkers (1989) Single-cell recording: When monkeys have to remember a location over time, cells in the PFC remain active
89Working Memory and the Brain Brain imaging studies with humans: PFC is active when we use working memoryBUT it isn’t the only area that’s active!Other areas in the frontal lobeAreas in the parietal lobeAreas in the cerebellumActivity occurs in many areas simultaneously