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Eye Witness Testimony Objectives 1.Be able to appreciate the importance of memory research 2.Be able to describe the key study 3.Be able to evaluate the.

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Presentation on theme: "Eye Witness Testimony Objectives 1.Be able to appreciate the importance of memory research 2.Be able to describe the key study 3.Be able to evaluate the."— Presentation transcript:

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2 Eye Witness Testimony Objectives 1.Be able to appreciate the importance of memory research 2.Be able to describe the key study 3.Be able to evaluate the key study

3 Think about this What is your earliest memory? What do you remember How old were you? Do you really remember it or only think you do from your parents stories?

4 Eye Witness Testimony An exercise in remembering –Listen to this story –Without looking draw both sides of a fifty pence piece –Learn the list of words I am going to read out now –Watch this clipWatch this clip –Write down all the words you can remember –Answer the questions about the film –Write down the story

5 Why is this area important? Devlin Committee (1976) –Those prosecuted after being picked in ID parade 82% convicted –Out of 374 cases where eyewitness only evidence 74% conviction

6 Why is this area important? Loftus 1974 –Asked students to judge guilt or innocence of a man Man had robbed a grocery store Murdered the shop keepers daughter –9 out of 50 judged him guilty on the evidence alone –36 out of 50 judged him guilty with an eyewitness –What do you think happened when told the eyewitness was not wearing his glasses and therefore could not see? 34 out of 50 still find him guilty

7 EYE WITNESS TESTIMONY? Loftus & Palmer –Loftus is a WOMAN (Elizabeth) TESTED –The validity of eye witness testimony –The effect of leading questions

8 LOFTUS & PALMER What is a leading question ? Have you seen the book? (leading Q) Have you seen a book?(not leading Q) Memory is NOT like a camera - we always reconstruct our memories

9 LOFTUS & PALMER The title of their paper was: The reconstruction of an automobile destruction Their research involved TWO experiments

10 LOFTUS & PALMER Experiment 1 The participants - 45 students The procedure - Students watched film clips of car accidents –there were 7 film clips –each student saw 4 clips –Evergreen safety council or Seattle Safety Department (standardised) After watching each film students did TWO things

11 LOFTUS & PALMER Experiment 1 1Write an account of what they had seen 2Answer questions about what they had seen One question was the CRITICAL QUESTION

12 LOFTUS & PALMER Experiment 1 THE CRITICAL QUESTION About how fast were the cars going when they (*******) each other There were five conditions (verbs) in the experiment (Five groups of students)

13 LOFTUS & PALMER Experiment 1 The five conditions (verbs) were CONTACTED HIT BUMPED COLLIDED SMASHED

14 LOFTUS & PALMER Experiment 1 Results –Contacted 31.8 –Hit 34.0 –Bumped38.1 –Collided39.3 –Smashed40.8

15 LOFTUS & PALMER Experiment 1 What conclusion can you draw from the results? What was the IV? What was the DV?

16 EYE WITNESS TESTIMONY A second experiment is needed as Two explanations for results in first study –Memory has been changed –Word acts as a cue to the speed that is expected (Demand Characteristic) So set up second study to find out

17 LOFTUS & PALMER - Experiment 2 The participants students The procedure - Students watched a one minute film which showed a 4 second multiple car accident

18 LOFTUS & PALMER - Experiment 2 After the film The participants were divided into THREE EXPERIMENTAL GROUPS

19 LOFTUS & PALMER - Experiment 2 GROUP 1 was asked How fast were the cars going when they HIT each other?

20 LOFTUS & PALMER - Experiment 2 GROUP 2 was asked How fast were the cars going when they SMASHED INTO each other?

21 LOFTUS & PALMER - Experiment 2 GROUP 3 was asked NO QUESTION about the speed of the cars

22 LOFTUS & PALMER - Experiment 2 ONE WEEK LATER The participants returned and were asked more questions Including a critical question

23 LOFTUS & PALMER - Experiment 2 THE CRITICAL QUESTION Did you see any broken glass? This question is not related to the speed directly

24 LOFTUS & PALMER - Experiment 2 Which group saw more broken glass? –Smashed YES16NO34 –HitYES7NO43 –ControlYES6NO44

25 LOFTUS & PALMER - Experiment 2 Probability of seeing broken glass based on estimate of speed Speed Smashed Hit

26 LOFTUS & PALMER - Experiment 2 What was the DV in the second experiment?

27 LOFTUS & PALMER - Experiment 2 What conclusion can you draw from the results?

28 EYE WITNESS TESTIMONY In this second study Memory has been altered As all participants asked the glass question Two types of info go into memory –Your perception –Information you get after the event

29 EYE WITNESS TESTIMONY List all the differences between study 1 and study 2

30 Q1 Which method was used by Loftus and Palmer? A.field experiment B.natural experiment C.quasi experiment D.laboratory experiment

31 Q2 Who were the participants in Experiment 1? A.students B.drivers C.accident witnesses D.accident victims

32 Q3 Which verb was not used in Experiment 1? A.hit B.smashed C.struck D.contacted

33 Q4 What was the dependent variable in Experiment 1? A.number of accidents recalled B.broken glass seen C.estimate of speed D.written account of accident

34 Q5 What was shown to participants in Experiment 1? A.videos of accidents B.film clips of accidents C.photographs of accidents D.CCTV of accidents

35 Q6 Which of the following was a dependent variable in Experiment 2? A.estimate of size of car B.whether broken glass seen C.participants written account of accident D.whether participant passed driving test

36 Q7 Which verb gave the highest speed estimate in Experiment 1? A.bumped B.hit C.collided D.smashed

37 Q8 How many participants were there in Experiment 2? A.45 B.15 C.150 D.50

38 Q9 Which of these was not a group of participants in Experiment 2? A.control B.‘hit' C.‘contacted' D.‘smashed'

39 Q10 How long was left between showing the films and asking about the broken glass? A.24 hours B.1 hour C.1 week D.1 month

40 Q11 Which group(s) 'saw' most broken glass? A.‘smashed' and ‘hit' B.‘smashed' C.control D.control and ‘hit'

41 Q12 What did Loftus and Palmer conclude about leading questions? A.They can influence memory. B.They have no effect on memory. C.They only effect students. D.They only work with car accidents.

42 Q13 What two types of information affect our memory? A.before and after an event B.before and during an event C.during and after an event D.immediately after and a long time after

43 Q14 What is a leading question? A.A question that leads a person to give a certain answer. B.A question that leads a person to give a wrong answer. C.A question that leads a person to give a right answer. D.A question that leads a person to lie.

44 LOFTUS & PALMER – A02 Is this study reliable? Is this study valid –Internal Is this study Ecologically Valid? Is this study ethical? Is the sample representative?

45 LOFTUS & PALMER – A02 How would you change the sample? –Effect on results –Effect on validity or reliability How would you change the procedure? –Effect on results –Effect on validity or reliability How would you change the method? –Effect on results –Effect on validity or reliability

46 Eye Witness testimony Do you think that UNSUPPORTED EYE WITNESS TESTIMONY should be sufficient evidence upon which to convict someone ?

47 Exam questions In the study by Loftus & Palmer, the subjects were shown film clips of car accidents. Identity two differences between witnessing these film clips and witnessing a real accident and, for each difference say how this might affect the results of the study. (4 marks)

48 Exam questions In the study by Loftus and Palmer on eyewitness testimony, the subjects gave different estimates of the speed of the cars depending on how the question was asked. Give two explanations for this. (4 marks)

49 Exam questions In the study by Loftus and Palmer (eyewitness testimony), the participants were shown film clips of car accidents. Suggest two ways in which the ecological validity of this study could be improved. (4 marks)

50 Exam questions a.In their study on eyewitness testimony, Loftus and Palmer suggest two kinds of information go into a person’s memory for a complex event. Identify one of these two kinds of information (2 marks) b. What does the existence of these two kinds of information tell us about memory? (2 marks)

51 Exam questions a.Identify the independent variable in the first experiment conducted by Loftus and Palmer on eyewitness testimony(2 marks) b. Outline how the independent variable was manipulated in the experiment(2 marks)


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