1. Psyco 350 Lec #9– Slide 1 Lecture 9 – Psyco 350, B1 Fall, 2011 N. R. Brown

2. Psyco 350 Lec #9– Slide 2 Outline Forgetting –decay –retrieval failure –Interference –Inhibition (directed forgetting) Interference In the Real-World –Hindsight Bias –Misinformation Effect

3. Psyco 350 Lec #9– Slide 3 Ebbinghaus(1885): The 1st Forgetting Function Main Findings: –AMOUNT of forgetting decreases w/ time Interpretation: –orgetting driven by decay; information lost at a constant rate.

4. Psyco 350 Lec #9– Slide 4 A Sample Decay Function Rate of forgetting constant over time Amount of forgotten/unit time  with time timestart Xfinish 0101100.50 50 1212 25 2323 12.50 3434 6.25 4545 3.125

5. Psyco 350 Lec #9– Slide 5 Studying PI & RI Classic studies: paired associate learning –study: cue-target word pairs (CUP-tree) –test: given cue, recall target (CUP-???) –manipulate presence, timing & similarity of additional targets

6. Psyco 350 Lec #9– Slide 6 Studying PI & RI General Findings: Cued Recall: Control > Experimental Similarity Effects: the more similar B is C, the more server the interference. DesignList 1List 2Test ProactiveA-BA-CA-?C? Exp D-EA-CA-?C?Control RetroactiveA-BA-CA-?B?Exp A-BD-EA-?B?Control

7. Psyco 350 Lec #9– Slide 7 Yet Another Demo 4 list 8 words/list Study  23 s of social interaction Test – recall 8 words from prior list.

8. Psyco 350 Lec #9– Slide 8 PI & RPI List 1List 2List 3List 4 1badgergoatdeerCleveland 2caribouskunkwalrusParis 3wolverineraccoonminkWinnipeg 4ottersquirrelbeaverDallas 5rabbitbearcoyoteBoston 6gophercougarwoodchuckLondon 7foxelklynxRome 8sealmousemooseHalifax

9. Psyco 350 Lec #9– Slide 9 PI & RPI: Background Brown & Peterson Task Review Task: learn triplet  filled delay  recall triplet Finding: –recall drops off very rapidly w/ delay Original Interpretation: –Forgetting caused by decay in STM –Forgetting indicates the rate of loss from STM Alternative Interpretation (Keppel & Underwood): –Forgetting caused by PI from similar materials Implication: PI should be reduced when new list differs from prior lists.

10. Psyco 350 Lec #9– Slide 10 Release from PI: Wickens (1972) Task: Standard Brown-Peterson Task Procedure: –Trials 1 though 3: triples drawn from same semantic category –Trial 4: triple drawn from different category

11. Psyco 350 Lec #9– Slide 11 Wickens (1972): Materials

12. Psyco 350 Lec #9– Slide 12 Wickens (1972): Results PI  (recall  ) across same-category trials. when category changes, Recall  Release from PI RPI  as similarity between initial category and new category  Finding generalize to real- world material (news stories)

13. Psyco 350 Lec #9– Slide 13 Gunter, Berry, Clifford (1981): RPI w/ News Stories Replicates Wickens with news stories. e.g., 3 sets of political stories  1 human interest story

14. Psyco 350 Lec #9– Slide 14 RPI: Activation-Discrimination Interpretation Activation: Concepts activated when accessed Activation decays rapidly Retrieval: search some (cued) portion of memory for most active concepts. -------------------------------------------------------------------------- PI: difficult to discriminate between many activated concepts. RPI: relatively easy to select active concepts among inactive ones.

15. Psyco 350 Lec #9– Slide 15 RI -- Recent learning impedes recall of prior material Slamecka (1960) – a lab demonstration Materials: 20-word long sentences drawn from text books. Study: Sentence present 1 word/3 seconds Test: Verbatim recall Design: # Learning Trials X # Interpolated Trials 202048

16. Psyco 350 Lec #9– Slide 16 Slamecka (1960): Results IMPORTANT: study-test delay constant across interpolation conditions Recall  w/ # learning trials (rehearsal effect) Recall  w/ # interpolated trials (RI)

17. Psyco 350 Lec #9– Slide 17 RI in the Real World General Idea: New task-relevant information makes to difficult or impossible to recall or reconstruct prior beliefs, knowledge, responses A GOOD thing: knowledge revision (Friedman & Brown, 2000) And a BAD thing: Hindsight Bias Misinformation Effect.

18. Psyco 350 Lec #9– Slide 18 Hindsight Bias: Typical 3-Phase Design Experimental Condition Phase 1: respond to a target question  R 1 How many rhinos live in Africa? Phase 2: Learn the answer to target question. There are 14,770 rhinos in Africa. Phase 3: Recall initial response (R 1 ).

19. Psyco 350 Lec #9 – Slide 19 Hindsight Bias: Typical 3-Phase Design Control Condition Phase 1: respond to a target question  R 1 How many rhinos live in Africa? Phase 2: Learn the answer to control question. The per capita GDP of Guam is $14,770. Phase 3: Recall initial response (R 1 ).

20. Psyco 350 Lec #9– Slide 20 Hindsight Bias Design Experimental Condition A-BA = # rhinosB = R 1 A-CA = # rhinosC = 14,770 A-?B?A = # rhinos?B? = R 1 Control Condition A-BA = # rhinosB = R 1 D-ED = Guam GDP C = 14,770 A-?B?A = # rhinos?B? = R 1

21. Psyco 350 Lec #9– Slide 21 Hindsight Bias(es) Recollection Bias: Correct recall of R 1 : Control > Experimental Reconstruction Bias (when R 1 not recalled): In Exp Condition -- Phase 3 response shifted in direction of Phase 2 information In Control Condition – Phase 2 information has no affect on Phase 3 response

22. Psyco 350 Lec #9 – Slide 22 Hindsight Bias: 2 mechanisms for 2 biases Recollection Bias: standard associate interference (Phase 2 answer competes w/ R 1 ) Reconstruction Bias: Phase 2 information cause a revision of underlying beliefs When R 1 not retrieved, answer reconstructed w/ revised information

23. Psyco 350 Lec #9 – Slide 23 Misinformation Effect General Phenomenon: memory for events distorted by exposure to inaccurate/misleading post-event information –benign aspect: post-event narration/discussion can alter autobiographical memories –forensic issue: post-event questioning can alter eyewitness testimony.

24. Psyco 350 Lec #9– Slide 24 Misinformation Effect: Basic Paradigm An event is witnessed (on tape) Post-event questioning used to introduce misinformation. Correct Post-event Information –Did the repairman set down his hammer before taking the calculator? Misleading Post-event Information –Did the repairman set down his screwdriver before taking the calculator? Neutral –Did the repairman set down his tool before taking the calculator?

25. Psyco 350 Lec #9 – Slide 25 Misinformation Effect: Basic Paradigm Test: Recognition for details of original event 2IFC = two item forced choice Did you see a hammer or a screwdriver? Finding: % correct as a function of post-event info type: correct > neutral >> misleading

26. Psyco 350 Lec #9 – Slide 26 Loftus, Burns, Miller (1978) Materials: –30 slides; pedestrian being hit. –traffic sign (STOP) appears in 1 slide. Questioning: –“Did another car pass the red Datsun as it passed the STOP/YIELD sign?” Delay: 20 min Test: 2IFC picture recognition picture w/ STOP vs picture w/ YIELD

27. Psyco 350 Lec #9 – Slide 27 Loftus, Burns, Miller (1978) Results: –Accurate post-event info: 75% cor. –Misleading post-event info: 40% cor. Loftus’ Interpretation: Memory change theory (knowledge revision) –misleading information replaces the original, which is permanently lost

28. Psyco 350 Lec #9 – Slide 28 Misinformation Effect: Other Interpretations Memory Coexistence (RI) Misleading information obscures original memory because it is more recent Support: –Memory better when original context is reinstated –Memory better if people are warned of misleading information before test

29. Psyco 350 Lec #9 – Slide 29 Misinformation Effect: Other Interpretations Source Monitoring Failure Errors reflect a failure to identify the source –People remember information, but misremember where it came from Information that people are mislead about is often that which they make source errors for

30. Psyco 350 Lec #9 – Slide 30 Misinformation Effect: Other Interpretations Biased Guessing Account McCloskey & Zaragoza (1985) Central Notions: –Target and Foil (misinformation) can coexist –Either or both can be forgotten –Magnitude of misinformation effect depends on: Prob (Target recalled) Prob (Foil recalled) %(Foil selected over Target)

31. Psyco 350 Lec #9 – Slide 31 Biased Guessing Account Magnitude of misinformation effect depends on: Prob (Target recalled) Prob (Foil recalled) %(Foil selected over Target) Implication: If foil removed from reco test, then MISLED = CONTROL Reason: “remembered” misleading inform no longer competing with original info.

32. Psyco 350 Lec #9 – Slide 32 Testing Biased Guessing Hypothesis Introduce modified recognition test. Predictions for recognition accuracy: –Biased Guessing: Modified Misleading = control –Memory Change: Modified Misleading < control misleading info should  memory for original info regardless of test Initial EventPost-EventReco Test Control“Stop”---“Stop” or “Yield Standard – Accurate“Stop” “Stop” or “Yield” Standard -- Misleading“Stop”“Yield”“Stop” or “Yield” Modified – Misleading“Stop”“Yield”“Stop” or “Detour”

33. Psyco 350 Lec # 9 – Slide 33 Rationale for Biased Guessing Prediction Control Condition: “S”  no “Y”; test: “S” or “Y” “S,” no “Y” no “S,” no “Y” “S,” no “Y” no “S,” no “Y” “S,” “Y” no “S,” “Y” Standard Test: “S”  “Y”; test: “S” or “Y” Modified Test: “S”  “Y”; test: “S” or “Z” “S,” no “Z” no “S,” no “Z”

34. Psyco 350 Lec # 9 – Slide 34 McCloskey & Zaragoza (1985): Method Stims: –79 slides of an office theft –4 s / slide –4 critical items: coffee jar, magazine, pop can, tool –Post-slide narrative 735-words long misinformation for 2 items; neutral for 2 items

35. Psyco 350 Lec # 9 – Slide 35 McCloskey & Zaragoza (1985): Method Procedure: view slides 10 minute filler read narrative 10 minute filler 36-item 2IFC recognition test: “ The man slide the calculator beneath the ___ in his tool box” standard test: hammer vs screwdriver modified test:hammer vs wrench

36. Psyco 350 Lec # 9 – Slide 36 McCloskey & Zaragoza (1985): Method Procedure: view slides 10 minute filler read narrative 10 minute filler 36-item 2IFC recognition test: “ The man slide the calculator beneath the ___ in his tool box” standard test: hammer vs screwdriver modified test:hammer vs wrench On Slide In Narrative Never encountered

37. Psyco 350 Lec # 9 – Slide 37 McCloskey & Zaragoza (1985): Results Standard Test: –replicates Misinformation effect: Misled << Control Modified Test: –consistent w/ Biased Guessing: Misled  Control access to original info unimpaired by post-event info. Consistent w/ Coexistence & Source Monitoring Accounts MisledControl Standard hammer vs screwdriver 37%72% Modified hammer vs wrench 72%75%

38. Psyco 350 Lec # 9 – Slide 38 Misinformation w/ Modified Procedure: Belli (1992) Materials: –44 slides (mother & child arguing) –4 crit slides (coffeemaker, blender, toaster) –500 word narrative w/ 2 misleading statements 2IFC modified reco test SlideNarrativeTest Controltoaster ---toaster vs blender Mod Misinfo toaster coffemaker toaster vs blender

39. Psyco 350 Lec # 9 – Slide 39 Misinformation w/ Modified Procedure: Belli (1992) view slides  Exp1 5-min delayExp3 5-day delay  read narrative  10 min delay  reco test Design – manipulates timing of misinformation

40. Psyco 350 Lec # 9 – Slide 40 Belli (1992): Results W/ 5-min delay:Mod Misled = Control consistent w/ Biased Guessing W/ 5-day delay:Mod Misled < Control (at lease) consistent w/ Coexistence & RI ControlMod Mis Exp 1 ns : 5-min delay95% Exp 3*: 5-day delay80%70%

41. Psyco 350 Lec # 9 – Slide 41 Blocking Hypothesis: Belli’s Explanation Post-event information impairs access to original traces when: original trace is weak post-event information is strong Original trace Trace for misinfomation Effect of mis-info on modified test strong noM&Z weak no???? weakstrongyesBelli

42. Psyco 350 Lec # 9 Slide 42 Misinformation Effect: My Take Memory impairment, coexistence, & source monitoring errors are not mutually exclusive As the work on Hindsight bias indicates, new information can: –modify existing information –coexist w/ existing information –block access to existing information Biased guessing is a problem in 2IFC situation – particularly when target & misinformation are of equal strength Nonetheless, bias to select foil in standard condition, indicates that post-event information is (some times) accepted as true & incorporated into event representation.