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Lecture 9 – Psyco 350, B1 Fall, 2011

Lecture 9 – Psyco 350, B1 Fall, 2011. N. R. Brown. Outline. Forgetting decay retrieval failure Interference Inhibition (directed forgetting) Interference In the Real-World Hindsight Bias Misinformation Effect. Ebbinghaus(1885): The 1st Forgetting Function. Main Findings:

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Lecture 9 – Psyco 350, B1 Fall, 2011

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  1. Lecture 9 – Psyco 350, B1Fall, 2011 N. R. Brown Psyco 350 Lec #9– Slide 1

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

  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. Psyco 350 Lec #9– Slide 3

  4. A Sample Decay Function • Rate of forgetting constant over time • Amount of forgotten/unit time  with time Psyco 350 Lec #9– Slide 4

  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 Psyco 350 Lec #9– Slide 5

  6. Studying PI & RI General Findings: • Cued Recall: Control > Experimental • Similarity Effects: the more similar B is C, the more server the interference. Psyco 350 Lec #9– Slide 6

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

  8. PI & RPI Psyco 350 Lec #9– Slide 8

  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. Psyco 350 Lec #9– Slide 9

  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 Psyco 350 Lec #9– Slide 10

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

  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) Psyco 350 Lec #9– Slide 12

  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 Psyco 350 Lec #9– Slide 13

  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. Psyco 350 Lec #9– Slide 14

  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 2 0 4 4 8 8 Psyco 350 Lec #9– Slide 15

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

  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. Psyco 350 Lec #9– Slide 17

  18. Hindsight Bias: Typical 3-Phase Design Experimental Condition Phase 1: respond to a target question  R1 • 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 (R1). Psyco 350 Lec #9– Slide 18

  19. Hindsight Bias: Typical 3-Phase Design Control Condition Phase 1: respond to a target question  R1 • 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 (R1). Psyco 350 Lec #9 – Slide 19

  20. Hindsight Bias Design Experimental Condition A-B A = # rhinos B = R1 A-C A = # rhinos C = 14,770 A-?B? A = # rhinos ?B? = R1 Control Condition A-B A = # rhinos B = R1 D-E D = Guam GDP C = 14,770 A-?B? A = # rhinos ?B? = R1 Psyco 350 Lec #9– Slide 20

  21. Hindsight Bias(es) Recollection Bias: Correct recall of R1: Control > Experimental Reconstruction Bias (when R1 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 Psyco 350 Lec #9– Slide 21

  22. Hindsight Bias: 2 mechanisms for 2 biases Recollection Bias: • standard associate interference (Phase 2 answer competes w/ R1) Reconstruction Bias: • Phase 2 information cause a revision of underlying beliefs • When R1 not retrieved, answer reconstructed w/ revised information Psyco 350 Lec #9 – Slide 22

  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. Psyco 350 Lec #9 – Slide 23

  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? Psyco 350 Lec #9– Slide 24

  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 Psyco 350 Lec #9 – Slide 25

  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 Psyco 350 Lec #9 – Slide 26

  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 Psyco 350 Lec #9 – Slide 27

  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 Psyco 350 Lec #9 – Slide 28

  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 Psyco 350 Lec #9 – Slide 29

  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) Psyco 350 Lec #9 – Slide 30

  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. Psyco 350 Lec #9 – Slide 31

  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 Psyco 350 Lec #9 – Slide 32

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

  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 Psyco 350 Lec # 9 – Slide 34

  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 Psyco 350 Lec # 9 – Slide 35

  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 In Narrative On Slide Never encountered Psyco 350 Lec # 9 – Slide 36

  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 Psyco 350 Lec # 9 – Slide 37

  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 Psyco 350 Lec # 9 – Slide 38

  39. Misinformation w/ Modified Procedure: Belli (1992) Design – manipulates timing of misinformation view slides   Exp15-min delay Exp35-day delay  read narrative  10 min delay  reco test Psyco 350 Lec # 9 – Slide 39

  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 Psyco 350 Lec # 9 – Slide 40

  41. Blocking Hypothesis: Belli’s Explanation Post-event information impairs access to original traces when: • original trace is weak • post-event information is strong Psyco 350 Lec # 9 – Slide 41

  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. Psyco 350 Lec # 9 Slide 42

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