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: 6th letter same or different color

Test: free recognition (click letters)

Results: global data

Loftus & Palmer (1974)

“Contacted”

32 mi/hr

Yes glass 11%

“Smashed”

41 mi/hr

Yes glass 32%

Depiction of actual accident

Leading question:

“About how fast were the cars going

when they contacted/smashed into

each other?”

1wk later:

“Did you see broken glass?”

Memory

construction

Ss watch slides of

accident

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: 1st, 3rd, 5th 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