Making a Case

Bullet points of the key studies

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  • Created on: 07-06-12 17:54

Interviewing Witnesses

Bruce - Recognising Faces

Fisher - Cognitive Interviews

Loftus - Weapons Focus 

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  • Recognising internal and external features of faces
  • Three lab experiments

    1) 30 ppts -  Composites, matching the internal and external

    2) 48 ppts - Celebrities, matching internal and external to celeb

    3) Photo Array, Being placed ito either or hard to match

  • The external features were matched at 35% rate , internal at 19.5%
  • That human brain recognises external features rather than internal 
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  • Weapons effect on recognising suspects
  • 36 students, into two groups, watched a robbery with the suspect showing either - 
    1)  gun
    2) cheque
  • After the clip was watched ,a questionnaire was answered and the participants had to choose the suspect from a line of photos.
  • In the cheque condition the suspect was identified more
  • Loftus concluded that in the condition , the participants focused on teh weopon rather than the suspects face 
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  • cognitive interview techniques in gainign information
  • 12 trained detectives in cognitive interviews
  • Real witnesses being interviewed
  •  The trained detectives were able to gain 47% more information
  • 94% of the information gained matched the evidence. 
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Interviewing Suspects

Mann - Detecting Lies

Inbau et al - Interrogation Techniques

Gudjohnsson - False Confessions 

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  • Police officers ability to detect lies
  • Watched videos of 14 real suspects, head and torso beign visible, up to 45 seconds long.
  • After the video , they had to anwser a questionnaire on if the statement was a truth or a lie and any ques used
  • The detection of lies was accurate with it increasign the longer the experience of the officer
  • teh ques mentioned was vagueness, gaze and story contradictioins 
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  • Interview techniques- Interrogation

  • nine techniques, examples are
    1) do not allow to cry or deny guilt
    2) Infer guilt through direct confrontation
    3) Allow two options, both leading to guilt
    4) show damaging facts

  • Used on those pre-thought to be guilty 

  • No used in the UK and can lead to false confessions in the mentally impaired 

  • Used in USA 
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  • A case study on false confessions
  • FC was a 17 year old youth,convicted of two murders
  • The first interview was 14 hours with breaks, in which FC was given leading questions, and it was questioned whether he was sexually impotent, he confessed to the murders 
  • In the second interview a solicitor was present and FC retracted his statement. After being questioned about his failed relationships he confessed again.
  • The tests at the prison showed he had good mental functioning and a average IQ
  • He confessed to escape the intolerable situation 
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Canter et al - Top down approach

Canter and heritage - bottom down approach

Canter - case study of john duffy

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Canter et al

  • Top down , organised/ disorganised crimes
  • 100 cases analysed, 3rd murder, variables analysed by court reports, police officers and interviews
  •  twice as many disorganised crimes
  • In disorganised, there were sex acts and vaginal **** in 2/3 of the cases
  • In organised 70% concealed the body above chance level
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Canter and Heritage

  • Bottom down approach
  • Content analysis of 66 sexual offences
  • there was 33 variables found including that of impersonal language to the victim , vaginal intercouse, surprise attack, no reaction and the victims clothes interfered with 
  •  understanding on how behaviour changes over time and if by same person 
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  • case study of John Duffy
  • was convicted of multiple murders but in jail confessed to more
  • Canter was assigned to build up a profile, he charted all murders on a database with help from police officers, based on the themes from the crimes
  • Canter developed a preliminary  profile used by officers, they narrowed down 2000 suspects to john duffy
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