lotus and palmer

• Background :

  Early stages of memory demonstrate how memories aren't accurate records of our experiences
• Aim

  Investigate how information supplied after an event (in form of a leading question) influences eyewitness testimony
• Method

  • 2 lab experiments
  • independent measures design
  • IV = verb used
  • DV = participants speed estimate - 1st experiment
  • DV = whether they believed they saw glass or not - 2nd experiment
• Experiment 1

  45 students from university of Washington

  Shown same 7 clips of traffic - ranged from 5-30 seconds

  Asked to write an account of accident

  Asked to answer specific questions but the critical (leading) question was

  'About how fast were going when they ______ into each other?

  Conditions : smashed, collided, bumped, hit,contacted
• Experiment 1 results

  Smashed = 40.8

  Collided = 39.3

  Bumped = 38.1

  Hit = 34.0

  Contacted = 31.8
• Explanation of Experiment 1 results

  1. memory was distorted by the leading questions
  2. Results could be due to response bias - they're not sure of the speed so they adjust their answer to fit with expectations
• Experiment 2

  Conducted to provide additional insight

  Find out if their memories had really been distorted by the verbal label

  150 students viewed short film

  Contained a 4 second scene of multiple car accidents

  3 conditions

  • Hit
  • Smashed
  • Control - not questioned

  One week later they returned and were asked series of questions including 'Did you see any broken glass?'
• Experiment 2 results

  Smashed = YES ( 16 ) NO (34 )

  Hit = YES ( 7 ) NO ( 43 )

  Control = YES ( 6 ) NO ( 44 )
• Explanation of results

  L & P argued there are 2 kinds of information that go into a persons memory - information obtained from perceiving an event and information supplied after the event

  These become integrated that we're unable to tell which is which.

  RECONSTRUCTIVE HYPOTHESIS
• Evaluation of Hypothesis

  • Many other factors could influence a persons memory
  • urges police and lawyers to ask as few leading questions as possible
• Evaluation of procedure

  strength

  • precise control - increase validity - cause and effect
  • high control - replicable - reliable
  • quantitative data

  limitations

  • lacks ecological validity
  • use of students - memories might be different - can't be generalised