Iriyama Shigeru; Ikema Airi; Kiriu Masayuki
Japanese Journal of Law and Psychology 2017 The Japanese Society for Law and Psychology
Information associated with suicide can cause confirmation bias among police officers, misleading them to make wrong determinations. In general, police officers are more likely to have a confirmation bias compared with coroners. This case study aimed to gain insight into the psychological phenomenon of confirmation bias in a death case by false-hanging. Employing the text mining approach, we analyzed the words describing the corpse from information in the published inquest records of the police officer, coroner, and forensic doctor. The result of a chi-square test and residual analysis showed that there was less corpse information in the re- cords of the police officer, who made a wrong determination, than the coroner and the forensic doctor. Fur- thermore, the police officer focused on information related to the instrument used for hanging (cord), neck pressure, and body weight more than the coroner and the forensic doctor.