Lost in a Shopping Mall

1
Lost in a Shopping Mall

• Loftus Pickrell
• 1995

2
Interference

• Proactive memory is disrupted by things we
  experienced earlier
• Retroactive memory is disrupted by things we
  experience later
• Modern research deals with retroactive
  interference
• New info invades us because we do not detect its
  influence
• The goal of this research is to understand how we
  become tricked by revised data about our
  experiences

3
Experiment

• Asked the question Is it possible to implant an
  entire false memory for something that never
  happened, rather than just alter a persons
  memory from a true event
• 3 males and 21 females ranging in age from 18-53
• Students at University of Washington
• Each subject was paired with a relative that
  provided information about 3 childhood experiences

4
Materials

• Subjects given a 5 page booklet that contained 4
  short stories from the subjects childhood
• 3 stories were true 1 was false
• The false story was always about being lost in a
  mall
• Each event was described in a paragraph at the
  top of the page, then subjects could comment
  about what they remembered on the rest of the page

5
Procedure

• Interview with relative where 3 childhood events
  were collected
• Relative helped construct the false event by
  telling where the subject could have conceivably
  gotten lost
• False event always contained
• Lost for a long period of time, crying, lost in a
  mall, found by elderly woman, and reunited with
  family

6
Procedure

• Subjects were told they were participating in a
  study to determine how and why some people
  remember certain things and not others
• If they did not remember the event, subjects
  could always put I dont know
• After completing booklet, 2 interviews were
  scheduled
• First interview was 1-2 weeks after completion of
  booklet
• Second interview was 1-2 weeks after that

7
First Interview

• At beginning of interview, subjects were reminded
  of the 4 events and asked to recall about them
• Rated clarity of memory (1-10)
• Rated confidence that given more time to think
  about event, they would be able to remember more
  (1-5)

8
Second Interview

• Essentially the same, except subjects were
  debriefed afterward
• Debriefing explained the attempt to create a
  false memory
• Subjects were asked to guess which event was the
  false one

9
Results

• 68 of true events remembered
• Initially, 29 remembered false event
• After first interview, one person said they no
  longer remembered the false event, so that left
  only 25 remembering the false event
• On average, more words were used to describe the
  true events than were used to describe the false
  events

10
Results

• Clarity ratings for false events tended to be
  lower than for true events
• Confidence ratings were low in general, but lower
  for the false events than for the true ones
• 19 of 24 correctly chose getting lost memory as
  the false one

11
Discussion

• These findings reveal that people can be led to
  believe that entire events happened to them after
  suggestions to that effect
• Because critics said being lost in a mall was too
  common of an experience, another experiment
  created false events of an overnight
  hospitalization
• If subjects couldnt recall the event, they
  received brief addition cues
• Results show that people will create false
  memories of childhood experiences in response to
  misleading information during repeated interviews

12
Hospital Study

• Subjects thought about new information in a
  schema, and they associate it with a previous
  experience
• The underlying schema is helpful for supporting
  the false event