How can an interviewer establish the behavioral norm of a subject?

Establishing the behavioral norm of a subject is crucial for a forensic interviewer, as it helps them understand what is typical for that individual and identify deviations that may indicate deception or stress. Asking questions that elicit the truth allows the interviewer to gauge the subject's usual responses, mannerisms, and emotional reactions, thus creating a baseline against which future statements can be measured. This approach encourages a more open dialogue, which can reveal how the respondent typically communicates and behaves under normal circumstances.

In contrast, asking vague questions might lead to ambiguous answers that don't provide a clear insight into the subject's behavior. Observing only body language offers limited information, as it does not take into account verbal responses and may lead to misinterpretation. Conducting a background check, while potentially informative about a subject's history, does not directly contribute to understanding their current behavioral norm during the interview process.