Forensic - Making A Case - Interviewing Suspects

detecting lies

interrogation techniques

false confessions

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Mann (2004)

Aim: to test police officers' ability to distinguish truths and lies during police interviews with suspects                                                                                    Method: Field experiment                                                                            Sample: 99 Kent police officers, 24f 75m, mean age 34.4; 78detectives 8trainers 4trafficofficers 9responseofficers

Procedure: video clips of 14 suspects, backed up establishing if telling truth or not. varied length-6 to 145 seconds. questionnaires about experience. watched clip and indicated if thought truth or lie and confidence. listed cues used to detect

Key Results: no significant diff between lie or truth accuracy-both significantly >chance(50%). most frequently mentioned cue was gaze then movements, vagueness, contradictions and fidgeting metioned as cues

Conclusions: levels of accuracy exceed other studies'. more experience=better at detecting lies. good lie detectors rely on story cues. police officers can detect liars above level of chance but pay attention to cues that aren't diagnostic cues to deceit.

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Mann (2004)


Evaluation Points:

  • determinism vs. free will
  • individual vs. situational

Method issues:

  • ethnocentric - only kent police officers, may all be similarly trained
  • low ecological validity - watching videos rather than real interviews

useful applications for police officers when detecting lies. investigates good ways to detect cues when suspect is lying

ungeneralisable - similarly trained police officers from same area. deterministic - does not look at other variables such as behaviours of different criminals

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Inbau (1986)

Reid 'nine steps' of interrogation in breif:

  • direct confrontation - suspect told directly, thought to have offended
  • offered chance to shift blame, suggestions/justifications to why (easier to admit guilt)
  • never be allowed to deny guilt, interrupt any to stop psychological adv.
  • try to give reasons why the couldn't commit crime, ignore to get confession
  • reinforce sincerity so suspect is receptive - good eye contact, first names
  • suspect becomes quiet and listens; move towards offering alternatives
  • pose 'alternative Q'- 2 choices for suspect; one more socially acceptable
  • get suspect to admit guilt in front of witnesses
  • document admission, sign confession, to avoid retraction later

Justifies use of these- being used on people presupposed to be guilty through their preliminary interview

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Inbau (1986)


Evaluation Points:

  • determinism vs. free will
  • reductionism vs. holism


  • could pose ethical issues (causing psychological harm to criminals being interviewed)
  • can be applied to real life situations
  • has shown to prove results during interviews
  • when used with the young or mentally impaired- highly likely to obtain false confession
  • prohibited in UK - use of psychological techniques and deception
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Gudjohnsson (1990)

Aim: to document a case of the false confession of a youth who was at the time distressed and susceptible to interrogative pressure                                    Method: case study                                                                                         Sample: A 17-year-old youth accused of two murders (FC). He was of average intelligence, suffered from no mental illness and his personality was not obviously abnormal                                                                                                   Background: 1987, 2 elderly women found battered to death in their home. savings missing, evidence of sexual assault. no forensic evidence to link FC to offence. denied access to a solicitor, interviewed at length until confession. next day, repeated confession in front of solicitor. year in jail, released by court after another person pleaded guilty to offences                                                            Interviews: 1st, 14hrs long denied at first later agreed after continuous accusation- leading q's, suggested sexually impotent. 2nd, in front of solicitor, retracted statement only to confess again                                                        Psychiatric exam: no ev. mental illness, IQ 94, 'stable extrovert'- personality Conclusions: 'coerced compliant' false confession-gave into pressure during interviews. shows that it can happen to anyone, not just the mentally ill. FC underwent change of personality, self-confidence improved.

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Gudjohnsson (1990)


Evaluation Points:

  • determinism vs. free will
  • individual vs. situational

Method issues:

  • psychological harm to suspects
  • false confession occur because of pressure meaning real criminal is not caught
  • shows it can happen to anyone, not just mentally ill

can be applied to real interview cases

causes psychological harm

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dominic wilson



making a case also involves subsection: "creating a profile". u missed it

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