Breaking the truth bias: the impact of comparable truth baselines and reality interview on veracity judgments by laypeople and police officers

This study examined whether embedding baselining within the Reality Interview (RI) protocol enhances intuitive veracity judgments. Baselining involves using a person's truthful verbal behavior as a reference point for evaluating the veracity of subsequent statements. We hypothesized that access to a comparable truth baseline (CTB) would improve veracity judgment accuracy. Eyewitnesses of a mock crime were interviewed with the RI and instructed to respond either honestly or deceptively. Laypeople (Experiment 1) and police officers (Experiment 2) evaluated these statements with or without a CTB. With a CTB, laypeople showed significantly higher accuracy in detecting deception and a reduced truth bias. However, police officers showed no improvement, maintaining chance-level performance regardless of statement veracity. These findings suggest that CTBs enhance lie detection in laypeople but not in trained professionals. Future research should explore tailored approaches to improving veracity judgments, perhaps incorporating specific guidelines on how to best use available cues.