Investigating investigators: examining witnesses' influence on investigators.
This research examined the influence of eyewitness identification decisions on participants in the role of police investigators. Undergraduate "investigators" interviewed confederate "witnesses" and then searched a computer database of potential suspects. The database included information on each suspect's physical description, prior criminal record, alibi, and fingerprints. Participants selected a suspect and estimated the probability that the suspect was guilty. Investigators subsequently administered a photo lineup to the witness and re-estimated the suspect's guilt. If the witness identified the suspect probability estimates increased dramatically. If the witness identified an innocent lineup member or rejected the lineup, investigators' probability estimates dropped significantly, even when pre-lineup objective evidence (e.g., fingerprints) was strong. Performance of participants acting as witnesses in two baseline studies was at chance. Therefore, participant-investigators greatly overestimated the amount of information gain provided by eyewitness identifications.
Dahl
Leora C
LC
University of Victoria, Victoria, British Columbia, Canada. ldahl@uvic.ca
Lindsay
D Stephen
DS
Brimacombe
C A Elizabeth
CA
D000704:Analysis of Variance; D001290:Attitude; D001955:British Columbia; D016009:Chi-Square Distribution; D003625:Data Collection / Q000379:methods / Q000592:standards; D003657:Decision Making; D003878:Dermatoglyphics; D044707:Forensic Sciences / Q000379:methods; D006167:Guilt; D006801:Humans; D007400:Interprofessional Relations; D035846:Law Enforcement / Q000379:methods*; D011939:Mental Recall; D015588:Observer Variation; D010781:Photography / Q000379:methods* / Q000592:standards; D016495:Police; D011336:Probability; D024382:Professional Role; D021641:Recognition, Psychology; D011996:Records; D011795:Surveys and Questionnaires