1. Psyco 350 Lec #3 – Slide 1 Lecture 3 – Psyco 350, A1 Winter, 2011 N. R. Brown

2. Psyco 350 Lec #3 – Slide 2 Outline Aspects of Modal Model: –STM vs LTM: Serial Position Curve –Properties of STM Capacity: Span Task Duration/Forgetting: Brown-Peterson Task Retrieval: Sternberg Task Problems w/ Modal Model

3. Psyco 350 Lec #2 – Slide 3 Modal Model: Evidence STM – LTM Distinction Assumption: –dual stores – STM & LTM: small amount of info held briefly in STM rehearsal enables and is required for transfer from STM to LTM Support: serial-position-curve phenomena

4. Psyco 350 Lec #2 – Slide 4 Free Recall & the Serial Position Curve Memory Tests Recognition Uncued Serial Cued Recall FREE

5. Psyco 350 Lec #2 – Slide 5 Free Recall Task

6. Psyco 350 Lec #2 – Slide 6 Free Recall Task List #1 – 15 words Instructions: There are 15 words on this list. When I say to, please write down as many of these words as you can.

7. Psyco 350 Lec #2 – Slide 7 Free Recall Task List #2 – 15 words; 20 s delay Instructions: There are 15 words on this list. When I say to, please write down as many of these words as you can.

8. Psyco 350 Lec #2 – Slide 8 In-Class Serial Position Curve

9. Psyco 350 Lec #2 – Slide 9 Free Recall & the Serial Position Curve Free recall: – uncued recall of studied items – order of output unconstrained Manipulate a variety of: –Encoding factors (e.g. presentation rate) –Storage factors (e.g., delay) Dependent variable: –% recalled as a function of serial position

10. Psyco 350 Lec #2 – Slide 10 Serial Position Curve Primacy: Good recall for 1 st few items Recency: Good recall for last few items on list

11. Psyco 350 Lec #2 – Slide 11 Modal Account of the Serial Position Curve Recency Effect produced by read-out from STM Primacy & “pre-recency” reflect information retrieved from LTM “Transfer” from STM to LTM caused by rehearsal. Implications: –Primacy & Prerecency:  w/ rehearsal –Recency: unaffected by rehearsal

12. Psyco 350 Lec #2 – Slide 12 Rundus (1971): Rehearsal & the Serial Position Curve Materials –20-word list –presentation rate: 5 s/word Task(s): –During study – overt rehearsal –During test – free recall

13. Psyco 350 Lec #2 – Slide 13 Rundus: Rehersal Protocols

14. Psyco 350 Lec #2 – Slide 14 Relation between Rehearsal & Recall Analysis: –# rehearsals for each word (position) –% recall for each word (position) Results: –“For a given amount of rehearsal, items from the initial serial positions are no better recalled than items from the middle of the list” – Rundus, 1971, p. 66

15. Psyco 350 Lec #2 – Slide 15 Relation between Study-time (Rehearsal) & Recall Glanzer & Cunitz (1966) manipulate study- time. Assume: study time & rehearsal related Results: –Primacy & Prerecency:  w/ study time –Recency: unaffected by rehearsal stydstyd

16. Psyco 350 Lec #2 – Slide 16 Relation between Filled Delay & Recall Glanzer & Cunitz (1966) Manipulate retention interval. Assume filled delay replaces contents of STM Results: –Primacy & Prerecency: un affected by delay –Recency  as delay  stydstyd

17. Psyco 350 Lec #2 – Slide 17 Amnesia & Serial Position Baddeley & Warrington (1970) H.M. – removal temporal lobe and hippocampus Clobbered Explicit memory. Yet – on immediate test, recency intact stydstyd

18. Psyco 350 Lec #2 – Slide 18 Dissociation: Evidence for Dual Store Dissociation – when “a single variable has different affects on two or more measures.” Evidence for separate stores, processes, or representation. Many variables have dissociative effect on the prerecency & recency portion of serial position curve. PrerecencyRecency Study time  = Post-list distraction=  Ant. Amnesia  = List Length  = Word Frequency 

19. Psyco 350 Lec #3 – Slide 19 Measuring STM Capacity: Memory Span Task Instructions: Recall the digits in the order presented.

20. Psyco 350 Lec #3 – Slide 20 Free Recall & the Serial Position Curve Memory Tests Recognition Uncued Serial Cued Recall FREE

21. Psyco 350 Lec #3 – Slide 21 Measuring STM Capacity: Digit-Span Task Span Test: Materials – random digits, words, etc Task – serial recall Span Defined – list length that produces accurate performance on 50% of trials

22. Psyco 350 Lec #3 – Slide 22 Capacity: Span Task Digit Span Defined: # of digits accurately recalled 50% of the time Standard Span: 7±2 digits Modal Model Interpretation (Miller, 1956): –STM Capacity: ≈ 7 “chunks”

23. Psyco 350 Lec #3 – Slide 23 Modal Model w/ 7 Slots – 1 chunk/slot

24. Psyco 350 Lec #3 – Slide 24 Chunking Chunking – “the process of combining information so that it takes up as little as possible of the limited space in STM” – Klatzky, p. 74 Chunking  span Why not a limitless STM? –“Chunk chunked chunks? Required: –Chunking scheme –Time to apply scheme

25. Psyco 350 Lec #3 – Slide 25 Extraordinary Digit-Span: SF Materials: –random digits –auditory presentation –1 digit/s Results: –After 45 days of practice: span = 83

26. Psyco 350 Lec #3 – Slide 26 SF: Digit Span

27. Psyco 350 Lec #3 – Slide 27 How did he do it? 1.Chunk (and elaborated) groups of digits into running times (or historical dates) 2.Devised in used “retrieval structure” to guide: Parsing of list in to units retrieval of items at test

28. Psyco 350 Lec #3 – Slide 28 SF: Chunking

29. Psyco 350 Lec #3 – Slide 29 SF: Retrieval Structure

30. Psyco 350 Lec #3 – Slide 30 Duration & Forgetting in STM Brown-Peterson Task: Initial attempt to measure duration of STM Procedure: –hear sub-span target set: 3 letters –count backwards for X s –recall target Manipulation – length of retention interval Assumption: –Counting task knocks out rehearsal –Measure of the rate of forgetting

31. Psyco 350 Lec #3 – Slide 31 Brown-Peterson: Main Finding In the absence of rehearsal, sub-span material is forgotten very rapidly from STM Initial interpretation: information rapidly decays from STM Note: w/ 0-delay, only 80% accuracy.

32. Psyco 350 Lec #3 – Slide 32 A Test of Decay Hypothesis Waugh & Norman (1965) -- Serial Probe Task Method: –auditory, 16 digit list, followed by probe digit –TASK: name the digit that followed the probe Manipulation: –location of probed item –Presentation time: 1digit/s vs 4 digits/s Decay prediction: –recall: 1 digit/s < 4 digits/s Interference prediction: –recall: 1 digit/s ≈ 4 digits/s

33. Psyco 350 Lec #3 – Slide 33 Waugh & Norman (1965) Results: Recall  w/ # of intervening items –consistent w/ both decay & interference Recall (more or less) unaffected by presentation rate –Consistent only w/ interference

34. Psyco 350 Lec #3 – Slide 34 Evidence for PI in Brown-Peterson Task Keppel & Underwood (1962) Competing Predictions: –Decay prediction: Does delay affect recall? NO –Interference prediction: Performance decline across trials? YES Conclusion: –Interference causes forgetting in STM

35. Psyco 350 Lec #3 – Slide 35 Studying Retrieval from STM

36. Psyco 350 Lec #3 – Slide 36 The Sternberg Task A Cognitive Psychology Classic Research Style: Paradigm-driven Exhaustive exploration of “parameter space” Disregard for: –intrinsic importance of phenomena –individual/cultural differences –emotion & motivation Slide 36

37. Psyco 350 Lec #3 – Slide 37 An Example: The Sternberg Task An Information Processing Classic: 2,500+ cites for two 1969 papers Task: Target set: short list of items Probe: a single item Target present  “Old” Target absent  “New”” Slide 37

38. Psyco 350 Lec #3 – Slide 38 STM Retrieval: 3 Possibilities Issue: –How do we access information in STM? –Is Item X in STM? Three possibilities: –Parallel – simultaneous access to all items. –Serial – consider 1 item at a time. Retrieval Models Parallel Serial Exhaustive Self- Terminating

39. Psyco 350 Lec #3 – Slide 39 STM Retrieval: 3 Possibilities Three possibilities: Parallel – simulators access to all items. Serial – consider 1 item at a time. –Self-terminating Stop when: target = content –Exhaustive Check each item on list Retrieval Models Parallel Serial Exhaustive Self- Terminating

40. Psyco 350 Lec #3 – Slide 40 Selecting between Retrieval Model: The Sternberg Task Task –Materials: Memory Set: N letters Probe: target letter –Question: Is probe in memory set? Manipulations –Set Size: 1 to 6 letters –Probe Type: positive (in memory set) negative (not it set)

41. Psyco 350 Lec #3 – Slide 41 Sternberg Task: Method

42. Psyco 350 Lec #3 – Slide 42 Competing Retrieval Model Predictions

43. Psyco 350 Lec #3 – Slide 43 Why Serial Models Make Different Predictions Additive Factors Logic (Radvansky, pp. 58-60)

44. Psyco 350 Lec #3 – Slide 44 Sternberg Task: Results RT  w/ set size Implication : serial Negative = Positive Implication: exhaustive

45. Psyco 350 Lec #3 – Slide 45 Sternberg’s Model

46. Psyco 350 Lec #3 – Slide 46 Problems / Serial Exhaustive Process Conceptual: –40 ms/comparison seems awfully fast. Empirical: –Repetition Effect (Baddeley & Ecob, 1973): Probe = T: RTWTN < RTWGN –Serial Position Effects (Corballis et al., 1972) Probe = T: TRWGN < RTWGN

47. Psyco 350 Lec #3 – Slide 47 Alternative Approach to Sternberg Findings Assumptions: memory set, the most active portion of LTM memory “searched” in parallel decision process: –“Yes”: probe-memory similarity > threshold –“No”: at deadline – similarity < threshold Set Size Effects: encoding: activation/item  as set size  retrieval: speed of assessment  as set size 