Memory inaccuracy Technical accuracy vs. content accuracy Exact vs. gist Constructive nature of memory Is this good or bad? Advantages/Disadvantages Depends on if need exact or gist Depends on if to-be-remembered is consistent or inconsistent with schema Depends on delay before testing What influences memory accuracy? Can memory be modified just by suggestion?
Von Restorff Effect Method: Study: 10 letters: 6 th letter same or different color Test: free recognition (click letters) Results: global data
Loftus & Palmer (1974) Depiction of actual accident Ss watch slides of accident Leading question: About how fast were the cars going when they contacted/smashed into each other? 1wk later: Did you see broken glass? Contacted 32 mi/hr Yes glass 11% Smashed 41 mi/hr Yes glass 32% Memory construction
Loftus et al. (1978) Method Slides: car stops at stop sign then turns & hits ped Question: Did another car pass the red Datsun while it stopped at the sign? MPI = misleading postevent information Non-MPI grp: stop sign vs. MPI grp: yield sign Recognition test: pictures Results MPI grp: More likely to recognize yield sign picture Conclusion Misinformation effect
Misinformation effect Can memory be modified by suggestion? Yes, but WHY? Loftus Memory-trace replacement hypothesis Eliminates original info Retroactive interference Impairs original info McClosky & Zaragoza Poor encoding of initial information Johnson Source confusion or poor source monitoring
Lindsay (1990) Method Slides: maintenance man stealing $ and computer Narrated by female 2 day delay Listed to story w/ incorrect details told to ignore Female or Male voice Memory test for source Results Conclusion Source monitoring Distinctiveness
Roediger & Geraci (2007) What is effect of aging on susceptibility for misinformation? HYPs? Less: b/c can t adequately encode/retrieve More: b/c more likely to accept or b/c poor source memory No difference: b/c above reasons combine Method: Slide sequence (repairman stealing wallet) Immediate - read narratives: MPI 0, 1, or 3x Test: y/n recognition or source test Results: Recognition test: Older accepted MPI 65% vs yng 29% (no effect of repetition) Source monitoring test: older decreased false responses, but no difference for younger
Age-related Misattribution Effect Ackil and Zaragoza s study: Subjects: 1 st, 3 rd, 5 th graders and college students Method: 8-min video depicting two brothers attending summer camp Immediately after, a summary is read with misleading information and omitting some salient scenes Surprise source memory test: told summary had mistakes, distinguish true and false events from video. One week later: subjects given same test
Susceptibility to misinformation Immediate 1wk Delay
Creating FM in people s lives Hyman et al. (1995); Lindsay et al. (2004) Method Parents provide description of early childhood events Ss asked to elaborate on true and false stories IV: delay Lindsay et al. (2004): added IV look at picture Results 20% of false events recalled with details 2x more FM when looking at picture Conclusion Misinformation effect Source monitoring error
Imagining childhood events DuBreuil et al. (1998) Method Ss told personality makes it likely to remember infancy and that memories are permanent Told that hospitals were influenced by research and effect of early visual stimulation mobiles Hypnotized and instructed to describe when 1day Results 61% report seeing mobile or something similar 33% believed report was probably or definitely real memory
Imagining childhood events Garry, Manning, Loftus & Sherman (1996) Session 1: Life events inventory (<10yrs) 1=definitely didn t happen; 8=definitely did happen Pretest answers for critical events Event M SD Mdn Range Percent 1-4* Got in trouble for calling 911. 1.97 2.27 1.0 7 87 Had to go to the emergency room late at night. 4.58 2.95 5.0 7 45 Found a $10 bill in a parking lot. 2.47 2.20 1.0 7 79 Won a stuffed animal at a carnival game. 3.84 2.49 3.5 7 55 Gave someone a haircut. 2.66 2.22 1.0 7 76 Had a lifeguard pull you out of the water. 2.18 2.04 1.0 7 84 Got stuck in a tree and had to have someone help you down. 1.87 1.93 1.0 7 92 Broke a window with your hand. 2.13 2.03 1.0 7 89 Overall 2.71 2.44 1.0 7 76 *1-4, responses on the eight-item scale indicating that a given event probably did not happen.
Garry, Manning, Loftus & Sherman (1996) 2 weeks later: asked to imagine 4 critical events "Imagine that it's after school and you are playing in the house. You hear a strange noise outside, so you run to the window to see what made the noise. As you are running, your feet catch on something and you trip and fall." Asked to picture each event and answer some questions Ss told that misplaced original questionnaire so needed to fill it out again
Garry, Manning, Loftus & Sherman (1996) Figure 1. Percent of events staying the same, increasing, and decreasing for subjects who initially responded 1 to 4 (responses indicating that the critical items probably did not happen).
Garry, Manning, Loftus & Sherman (1996): Imagination inflation Overall: 8.2% greater for imagined vs not imagined
Can you implant whole memories? Piaget: false memory of kidnapping Loftus & Pickrell (1995) Suggest to sibling/child lost in mall when 5yr 6/24 reported full or partial memory of event Bruck, et al. (1995) True event at 5yr: vaccine at doctor 1yr later: interviewed 4x Misinformation incorporated into memory Pezdek & Hodge (1999) Plausible (lost in mall) vs implausible event (enema) Ask child for more details of event More likely for plausible event (14/39 kids vs. 3/39)
Variables that affect FM Age IQ Memory Knowledge Self-esteem Stress Compliance Time delay Repetition of recall