Comparative analysis of true or false statements with the source monitoring model and the cognitive interview: special features of the false accusation of innocent people

Abstract

We describe two experiments designed to verify whether the source monitoring (SM) model categories and the cognitive interview (CI) contribute to distinguishing true from false statements. We used a 2 Type of Interview (Structured/Cognitive) × 2 Statement Condition (True/False) design with 18 interviewers in a sample group of 240 gender-matched university students being interviewed about a film fragment. In Experiment 1, participants who lied exculpated the protagonist from rape, whereas in Experiment 2 their lies were aimed at accusing an innocent person. As dependent variables we used criteria from the SM: details, supporting memories, thoughts and feelings and cognitive operations. The results suggest that the statements of honest participants interviewed using the CI provided more overall information than those obtained under any other condition. When a lie is aimed at exculpating someone from criminal behaviour, statements involve more cognitive operations and less sensory, temporal and contextual information, but only when the structured interview (SI) is used. When the lie is aimed at falsely accusing someone, the SI and the CI produce similar results. We discuss the forensic importance of these findings.

Keywords:

• reality monitoring (RM)
• cognitive interview
• deception
• forensic
• witness