Memory and Cognition

1. Memory and Cognition PSY 324 Topic 5: Short-Term & Working Memory Dr. Ellen Campana Arizona State University

2. Modal Model of Memory

3. Modal Model of MemoryAtkinson & Shiffrin (1968) Rehearsal • Three stages of memory • Input, Output, Rehearsal (a control process) Input Sensory Memory Short- term Memory Long- term Memory Output

4. Modal 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 15-30 seconds. Control processes can extend this. • Long-term Memory (LTM): holds a large amount of information for years, even decades • Control processes: active memory strategies controlled by individual (example: rehearsal)

5. Control Processes • Some control processes maintain info in STS • Rehearsal (repeat the items over and over) • Chunking (make connections between items) • Visualization • Some control processes affect transfer between STS and LTS (storage and retrieval) • Memorization • Recall • You can only process information in STS

6. Sensory Memory

7. Sensory Memory • Sensory memory is very short • Allows you to see the “trail” of a sparkler • Allows you to see movies (flipbook, tachistoscope) • Auditory Sensory Memory is also called • Echo • Visual Sensory Memory is also called • Persistence of vision • Iconic Memory / Visual Icon

8. Sperling (1960): Iconic Memory X M L T A F N B C D Z P Whole report condition X F D Z C

9. Sperling (1960): Iconic Memory X M L T A F N B C D Z P Partial report condition X M L T

10. Sperling (1960): Iconic Memory • What’s the point? • Sperling was studying visual sensory memory • Before his study, people thought that visual sensory memory could only hold 4-5 items (full report cond) • The other conditions in his study showed that • It’s true that people can only report 4-5 items before memory decays (or fades away) • BUT sensory memory actually encodes the whole scene • Conclusion: Sensory Memory has a large capacity, but fast decay

11. Sperling (1960): Iconic Memory X M L T A F N B C D Z P Partial report delayed condition M

12. Sperling (1960): Iconic Memory • Summary of conditions • Whole report condition • All 12 letters flash on/off -> 1s. delay -> report any • Partial report condition • All 12 letters flash on/off -> auditory cue to row -> report just that row • Partial report delayed condition • All 12 letters flash on/off -> 1s. Delay -> auditory cue to row -> report just that row

13. Sperling (1960): Timing of Decay • What’s the point? • Sperling wanted to get a clearer picture of just how fast sensory information decays • Stronger support of his hypothesis that sensory memory has large capacity and fast decay • Conclusion: Within just 1 second, most of sensory memory decays, leaving only what was moved to STS via attention.

14. Moray, 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 showed • Echoic memory has larger capacity and slower decay than visual iconic memory

15. Modalities of Sensory Memory • Modality: the “channel” (Broadbent) that different inputs come in through • Auditory, visual, tactile, etc. • Sensory memory is modality specific • Saying “ba, ba, ba” while receiving auditory input messes up echoic, but not iconic memory • A visual mask messes up visual memory, but not auditory memory • Mask: for control in experiments (as in demo)

16. Change Blindness

17. Change Blindness

18. Change Blindness

19. Sensory Memory Now • In 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 memory • Still thought to have large capacity and fast decay • Thought to be important for • Collecting input • Holding input during initial processing • Filling in “blanks” (movies, static, etc.)

20. Short-Term Memory(STM)

21. Modal Model of MemoryAtkinson & Shiffrin (1968) Rehearsal • Three stages of memory • Input, Output, Rehearsal (a control process) Input Sensory Memory Short- term Memory Long- term Memory Output

22. Short-Term Memory • Short-term memory allows you to: • Understand sentences • Do arithmetic • Dial a phone number • Navigate from one place to another • Know where we are and what we’re doing right now • Memory for current tasks, last few minutes • Momento: main character had STM, not LTM • Clive Wearing: Real-world case in book

23. Issues 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 lot • Rehearsalseems to extend duration • Chunking seems to extend capacity

24. Duration of Short-term Memory • Brown (1958) / Peterson & Peterson (1959) • Same studies at the same time, same results • Step 1: three letters + one number given • Step 2: count backward from number • Step 3: 3-18 s. delay (while counting backward) • Step 4: recall three letters

25. Duration of Short-term Memory • Brown (1958) / Peterson & Peterson (1959) • Same studies at the same time, same results FIRST TRIAL ONLY Percent Recalled 3 18 Delay

26. Duration of Short-term Memory • Brown (1958) / Peterson & Peterson (1959) • Same studies at the same time, same results THIRD TRIAL ONLY Percent Recalled 3 18 Delay

27. Duration of Short-term Memory • Brown (1958) / Peterson & Peterson (1959) • Same studies at the same time, same results MANY TRIALS LATER Percent Recalled 3 18 Delay

28. Duration of Short-term Memory • Brown (1958) / Peterson & Peterson (1959) • Same studies at the same time, same results AVERAGE OVER ALL TRIALS Percent Recalled 3 18 Delay

29. Duration 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 occurs • Recall of letters after long delays decreases as the series of trials gets longer

30. Duration of Short-term Memory • What’s the point? • Peterson & Peterson / Brown were interested in decay of short term memory • It turns out, their studies demonstrate that another type of forgetting that happens in STM: proactive interference • What is already in STM affects ability to add new things • Larger point is that forgetting in STM occurs through both decay and interference (proactive and other types too) – effective duration is 15-20s.

31. Capacity of Short-term Memory • Capacities can vary from person-to-person, measured by digit span • Get out some paper and something to write with, we’re going to calculate your digit span

32. Capacity 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.

33. Capacity of Short-term Memory 2 1 4 9 3 9 6 7 8 6 4 9 7 8 4 7 3 8 2 0 1 5 8 4 2 6 1 4 3 2 4 8 2 3 9 2 8 0 7 5 8 5 2 9 8 1 6 3 7 GO! GO! GO! GO! GO! GO! GO!

34. Capacity of Short-term Memory 2 1 4 9 3 9 6 7 8 6 4 9 7 8 4 7 3 8 2 0 1 5 8 4 2 6 1 4 3 2 4 8 2 3 9 2 8 0 7 5 8 5 2 9 8 1 6 3 7 How many digits were in the longest row that you got completely right? That’s your digit span.

35. Capacity 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…..

36. Capacity 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)

37. Capacity of Short-term Memory • Miller (1956): People can remember 7±2 …. • Digits • Words • Numbers (with multiple digits) • Phrases • We can remember more if it’s organized • Chunking is combining smaller units into larger meaningful units, to improve capacity

38. Chunking • Chunking involves using Long-term memories to organize information in Short-term memory • Ericcson and coworkers (1980) • College student had digit-span of 79 after training • Chunked digits into meaningful times for running, a sport he was familiar with • Chase and Simon (1973) • Chess players chunk information based on meaningful points within a game of chess

39. Chunking • Chase & Simon (1973) Random Arrangements Meaningful Arrangements Correct Piece Placements Master Beginner Master Beginner

40. Chunking & Information Coding • What’s the point of all these chunking studies? • Capacity is related to how information is represented • Recall our last discussion of how information is represented, during “Cognition and the Brain” • Specificity coding vs. Distributed coding • Dealt with how information is represented by neurons’ firing rates • This is called a physiological approach to coding • We can also take a mental approach to coding

41. Information Coding • Mental approach to coding • More abstract than physiological approach • Deals with how things are represented in the mind / thoughts • Three Types of Coding • Auditory Coding – represented as a sound • Visual Coding – represented as an image • Semantic Coding –represented through meaning

42. Auditory Coding • Conrad (1964) • Participants saw target letters (quickly flashed) • Then they wrote them down • Mistakes were made • Not 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)

43. Semantic Coding • Wickens and Coworkers (1976) • Participants divided into groups • Groups heard lists with different meanings (fruits, professions, meats, etc.) • Proactive Iterferecen for same list-TYPE repeated • Category switch caused release from proactive interference • Effect was larger for categories that were less similar • Evidence for semantic (meaning) coding

44. Short-term Memory Today • The Modal Model had a nice clean vision of Short-term Memory • All-purpose store with 15-20s duration and capacity of 7±2 • Simply holds information • How information is coded affects how much information fits in STM, but not much else • This view of STM turned out to be too simple, so it has been replaced with working memory

45. Working Memory

46. Modal Model of MemoryAtkinson & Shiffrin (1968) Rehearsal Input Sensory Memory Short- term Memory Long- term Memory Output

47. Working MemoryBaddeley & Hitch (1974) Input Sensory Memory Central Executive Long- term Knowledge Phonologal Loop Visuospatial Sketchpad

48. Comparing Memory Models • Short-term Memory (Attkinson & Shiffrin) • Single component for all types of info • Mainly used for holding information for a short time • Working Memory (Baddeley & Hitch) • Three components: • Central Executive • Visuospatial Sketchpad • Phonological Loop • Used for manipulation of information during complex cognition

49. Components of Working Memory • Phonological Loop • Holds verbal and auditory information • Coding or source can determine whether it’s verbal/auditory information or not • Visuospatial Sketch Pad • Holds visual and spatial information • Central Executive • Pulls info from long-term memory, coordinates other components, directs and maintains attention…

50. Phonological Loop A component of working memory