Abstract

Investigative directors have controlling power on investigative actions. However, it is shown that distortions are problematic in paper records. Therefore, this study examined the effect of distortions of paper records on investigative directors’ decision making, and the methods and frequency of the control of the directors. In the study 1, total 90 investigative directors reviewed one of the three versions of paper records (30 ‘original’, 30 ‘committed’, 30 ‘omitted’), then the directors were asked to evaluate the suspect’s veracity. The Study 2 surveyed 63 directors including how and how often they examine the authenticity of paper records. The results showed that (1) directors in the distorted records groups evaluated the suspect more deceptive than those in the original record group did. (2) The omitted paper record also had significant effect on the directors’ evaluations about the suspect’s veracity. (3) Investigative directors rarely checked the authenticity of the documents by watching video records or participating in interrogation procedures. In the conclusion, ‘A Model of Learning Effect and Selective Reinforcement Effect in Distortions of Paper Records’ and improvement methods were suggested based on the results of the studies, and implications and limitations of the study were disscussed.