Psychology 221: Short-Term Memory PDF

2025-01-28 Psychology 221: Intro. to Cog. Psych. Short-term/Working Memory Thomas Spalek Week 4 Chapter 5 1 1  2025-01-28 Pl...

2025-01-28 Psychology 221: Intro. to Cog. Psych. Short-term/Working Memory Thomas Spalek Week 4 Chapter 5 1 1  2025-01-28 Plan for Today ▪ Short-term Memory ▪ Capacity ▪ Forgetting ▪ Representation ▪ Retrieval ▪ Working Memory ▪ Different Memory Systems or not? Psyc 221 2 2  2025-01-28 Information Processing Model Atkinson and Shiffrin (1968) attention Psyc 221 3 3  2025-01-28 Characterizing Memories Transfer: How is information copied into the store? Capacity: How much information can the store hold? Forgetting: How does information get lost from the store? Representation: What is the format of information in the store? Retrieval: How is information recovered from the store? Psyc 221 4 4  2025-01-28 Capacity of Short-term Memory George Miller’s (1956) Miller analysis of short- term memory capacity (7 ± 2 chunks) Psyc 221 5 5  2025-01-28 The Unit of Short-term Memory Chunk: a collection of elements that are strongly associated with one another but weakly associated with elements of other chunks anything in working memory which has a unitary representation in long-term memory Psyc 221 6 6  2025-01-28 STM Chunk as a Pointer to LTM The Wizard of Oz Long- “heads” table term 6 H Memory Pepsi Cola Madonna Short-term Memory Psyc 221 7 7  2025-01-28 The Unit of Short-term Memory Chunk: a collection of elements that are strongly associated with one another but weakly associated with elements of other chunks anything in working memory which has a unitary representation in long-term memory Recoding: packing more information into each chunk, given that the number of chunks is limited Mnemonic: a technique for improving memory (from the Greek, “mneme,” meaning memory) Psyc 221 8 8  2025-01-28 Change Detection Task for Estimating STM capacity Psyc 221 9 9  2025-01-28 Are all Chunks Created Equal? Alvarez and Cavanaugh (2004) Used the change detection procedure Used colored squares as well as more complex objects Psyc 221 10 10  2025-01-28 Different Capacity Estimates Psyc 221 11 11  2025-01-28 Forgetting in STM Is loss of information due to decay? Psyc 221 12 12  2025-01-28 Brown (1958); Peterson & Peterson (1959) 1 Proportion Correct 0.8 0.6 0.4 0.2 0 3 6 9 12 15 18 Retention Interval (sec) Psyc 221 13 13  2025-01-28 Waugh & Norman (1965) 6 2 9 3 1 4 6 9 7 5 8 3 1 5 7 3 Probe: 4 Report: 6 Read at a rate of 1/s or 4/s 9 interfering items Psyc 221 14 14  2025-01-28 Waugh & Norman (1965) 1 Proportion Correct 0.8 1 per second 4 per second 0.6 0.4 0.2 0 1 2 3 4 5 6 7 8 9 10 11 12 Number of Interfering Items Psyc 221 15 15  2025-01-28 Interference Alternative explanation: poor remembering caused by interference by the counting task. RI – Retroactive interference – newer material interferes backward in time with your recollection of older items Psyc 221 16 16  2025-01-28 Keppel & Underwood (1962) 1 Proportion Correct 0.8 0.6 0.4 0.2 0 3 6 9 12 15 18 Retention Interval (sec) Psyc 221 17 17  2025-01-28 Interference Alternative explanation: poor remembering caused by interference by the counting task. RI – Retroactive interference – newer material interferes backward in time with your recollection of older items PI – proactive interference – when older material interferes forward in time with your recollection of the current stimulus Psyc 221 18 18  2025-01-28 Wickens (1972): “Release from PI” Trial 1: apple, pear, kiwi Trial 2: peach, banana, strawberry Trial 3: plum, raspberry, orange Trial 4: Control Group: pear, grapefruit, lime Experimental Group: lawyer, dentist, engineer.. Psyc 221 19 19  2025-01-28 Wickens (1972) 1 Proportion Correct Control 0.8 Experimental 0.6 0.4 0.2 0 1 2 3 4 Trial Number Psyc 221 20 20  2025-01-28 Recoding & Rehearsal Verbal information is recoded into acoustic (auditory) format in WM (even when visually experienced) Conrad (1964) - sound-alike errors Wickelgren (1965) – RI from rhyming distractor task Psyc 221 21 21  2025-01-28 Semantic Codes Wickens’ “release from PI” demonstrates importance of semantic codes in short-term memory Professions Percent Flowers Recall Vegetables Fruits (control) 1 2 3 4 Trial Psyc 221 22 22  2025-01-28 Mental Rotation Ability to mentally rotate images indicates visual coding in working memory Psyc 221 23 23  2025-01-28 Shepard & Metzler (1971) Psyc 221 24 24  2025-01-28 Saul Sternberg key papers in 1966, 1969 developed a way to measure working memory retrieval using recognition, not recall used response time (RT) because accuracy would be perfect Psyc 221 25 25  2025-01-28 Scanning Working Memory study: present from 1 to 5 digits rapidly (1 second each) test: present a probe digit that either was or was not in the studied set (match or mismatch) record RT from onset of probe to press of YES or NO button Psyc 221 26 26  2025-01-28 Retrieval from STM The Sternberg (1966) paradigm: T K T “yes” Q Memory Set Test Probe Response (1-5 items) (old or new) (yes or no) Psyc 221 27 27  2025-01-28 Sequential/Serial Scan if scanning is one at a time, one item Response Time (RT in msec) 600 550 after another, then 500 RT should increase 450 with set size 400 if each comparison 350 1 2 3 4 5 takes the same Memory Set Size amount of time, then the increase should be linear Psyc 221 28 28  2025-01-28 Two Flavours of Serial Search Response Time (RT in msec) Response Time (RT in msec) 600 600 550 550 500 500 450 450 400 400 350 350 1 2 3 4 5 1 2 3 4 5 Memory Set Size Memory Set Size Serial Exhaustive Search Serial Self-Terminating Search Psyc 221 29 29  2025-01-28 Parallel Scan if scanning Response Time (RT in msec) 600 examines all items 550 at once, then RT 500 should be constant 450 over set size 400 makes the same 350 prediction for NO 1 2 3 4 5 and YES, but NO Memory Set Size may be a little slower (checking) Psyc 221 30 30  2025-01-28 Scan Models Parallel Serial Psyc 221 31 31  2025-01-28 Sternberg (1966) Results Response Time (RT in msec) 600 No 550 500 Intercept = 397 ms Yes 450 400 Slope = 38 ms/item 350 1 2 3 4 5 Memory Set Size Psyc 221 32 32  2025-01-28 Additive Factors Model Repeat for read & each item encode probe Slope compare probe to memory set decide if there is a match Intercept execute the response Psyc 221 33 33  2025-01-28 Alan Badley Baddeley & Hitch (1974) shifted the emphasis from passive storage (short-term memory) to active processing (working memory) multiple components Psyc 221 34 34  2025-01-28 Working Memory Central Executive: directs and controls all WM functions Visuo-spatial Sketchpad: a slave system for holding visual information Phonological Loop: a slave system for holding and recycling auditory/acoustic information – Articulatory (Rehearsal Process) Loop: a process for recycling, using subvocalization – Phonological Store: a structure for holding acoustic information Episodic Buffer: where information from different modalities and sources is bound together Psyc 221 35 35  2025-01-28 Baddeley (2000) Psyc 221 36 36  2025-01-28 Working Memory WM is set up to process different types of information simultaneously WM has trouble when similar types of information are presented at the same time Psyc 221 37 37  2025-01-28 Brooks (1968) Point (Spatial) O Corner Response F 1 OUT IN 2 OUT IN (Verbal) 3 OUT IN 4 OUT IN I Say Out Loud 5 OUT IN “Out” or “In” 6 OUT IN 7 OUT IN (Spatial) 8 OUT IN 9 OUT IN 10 OUT IN Scan a memorized sentence for the occurrence of nouns (Verbal) and either say “Yes” or “No” (Verbal), or point to them on a paper (Spatial) Psyc 221 38 38  2025-01-28 Brooks (1968) Results When required response was in the same format as the primary scanning task, performance suffered Harder to do pointing, than verbal, response while scanning the outside corners of a letter Harder to do verbal, than pointing, response while scanning a sentence for nouns Psyc 221 39 39  2025-01-28 Are Sensory Memory and Working Memory different? SM WM input from the senses input from SM infinite capacity limited (7±2) capacity forgetting due to decay forgetting due to interference (decay?) raw representation largely phonological representation retrieval via one at a retrieval via serial time attentional exhaustive search selection based on based on identity physical characteristic Psyc 221 40 40  2025-01-28 Are Working and Long-term Memory different? Serial Recall: recall the items in the same order as they were presented Free Recall: recall the items without regard to their order of presentation Psyc 221 41 41  2025-01-28 The Serial Position Curve 1 0.9 Proportion Correct 0.8 primacy recency 0.7 0.6 0.5 asymptote 0.4 0.3 0.2 0.1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Serial (List) Position (e.g., Murdock, 1962) Psyc 221 42 42  2025-01-28 Serial Position Definitions Primacy: Superior memory for the beginning information in a sequence Asymptote: Average memory for information in the middle of a sequence Recency: Superior memory for the ending information in a sequence Psyc 221 43 43  2025-01-28 Varying Distraction 1 0.9 seconds of distraction Proportion Correct 0.8 0.7 0 0.6 6 0.5 12 0.4 0.3 30 0.2 0.1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Serial (List) Position (e.g., Glanzer & Cunitz, 1966) Psyc 221 44 44  2025-01-28 Word Frequency 1 0.9 high freq (common) Proportion Correct 0.8 0.7 0.6 0.5 low freq (rare) 0.4 0.3 0.2 0.1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Serial (List) Position (e.g., Sumby, 1963) Psyc 221 45 45  2025-01-28 Rate of Presentation Psyc 221 46 46  2025-01-28 The Concept of Dissociation Dissociation: an independent variable affects one situation or theoretical entity differently from another (e.g., distraction affects WM but not LTM) Double Dissociation: two situations or theoretical entities are affected in opposite ways by one or more independent variables (e.g., distraction affects WM but not LTM; rate of presentation and word frequency affects LTM but not WM) Psyc 221 47 47