Mann - lie detection technique

• Sample

  Tested 99 Kent police officers (24f, 25m), 78 detectives, 4 traffic officers, 8 trainers and 9 uniform officers to distinguish truth from lies in police interview with a suspect
• Procedure

  • Saw video clips taken from 14 police interviews and were asked to judge if the suspect was telling the truth or lying in each one and how sure they were on a 7-point scale
  • Were asked what cues they used to judge if they were lying
• Results

  • Police officer's ability to judge/detect lies and truth was significantly better than chance (accuracy in judging lies 66.2% and truth 63.6%)
  • Experience in interviewing correlated with truth accuracy and lie accuracy
  • Cues that lead to better accuracy were contradictions in the story rather than those related to body language