When introducing the concept of strategic use of evidence to students it quickly becomes apparent that many have never thought of evidence as anything than something you reveal to force the suspect to confess or to demonstrate the superiority of their own interpretation or the understanding of the case. Rarely is it seen as an opportunity for the interviewee to provide an explanation from their perspective. Then reveal the concept of introducing evidence not only with an overall strategic plan, but recognizing when tactically it may be best to reveal a certain item of evidence results in many blank quizzical faces.
The consequences of different timings of evidence disclosure are the subject of a number of academic studies. They primarily observe their effects on suspect interviews, with the primary focus on the effectiveness of eliciting statement-evidence inconsistencies and novel investigative information. The main methods described are: Early, Late, Gradual, and Adaptive disclosure.
Evidence Disclosure Methods
Early Disclosure:In this method, the interviewer discloses available evidence at the beginning of the interview before asking the suspect to provide their account. The purpose of this can be to allow the interviewee to be aware of the apparent strength of evidence at the beginning of the interview. This reveals the extent of the interviewer's knowledge and may reduce resistance. Additionally, it may be a rapport-building technique in more cooperative interview contexts to encourage openness.
The research conducted determined that this strategy tends to reduce the amount of new investigative details provided by the interviewee. It is also possible for the interviewee to tailor their responses to match the facts presented. This will reduce the ability to observe any verbal cues of deception as inconsistencies and contradictions diminish when the interviewee knows what the interviewer knows. This also results in a lower cognitive load on the interviewee. In the case of a cooperative interviewee the perceived transparency may help with rapport in some situations.
Overall, Early disclosure narrows the gap between what the suspect knows and what they think the interviewer knows, thereby limiting diagnostic opportunities. Key research can be summarized as follows:
- Granhag & Hartwig (2008): Early disclosure results in similar statement patterns between truth tellers and liars, making detection difficult.
- Oleszkiewicz & Watson (2020): Meta-analytic evidence confirms early disclosure produces lower effect sizes for deception detection and novel information elicitation.
- Kelly et al. (2024): Reinforces that early disclosure is the least effective approach in terms of eliciting critical or new information.
Late Disclosure:Introduced to exploit differences in verbal behavior between guilty and innocent suspects, the late disclosure method involves the interviewer encouraging the suspect to provide an open-ended narration first. Evidence-focused questions are then asked before the suspect is made aware of the specific evidence the interviewer possesses. The theory behind this method is that withholding evidence will increase the number of statements that contradict the evidence among guilty suspects, while the statements of innocent suspects should remain consistent regardless of when the evidence is presented.
The research examining this strategy observed that allowing an interviewee to provide a full account may not maximize new investigative information, but revealing evidence can prompt retractions and changes to statements reducing interviewee credibility. The inconsistencies and contradictions between statements made and known facts enhances the ability to detect deceptive cues. In addition, the cognitive load on the interviewee is higher since they do not know the extent of the evidence held by the interviewer. There is also a risk of withdrawal or reduction of cooperation if the interviewee feels cornered or surprised by the production of evidence.
Overall, Late disclosure creates a contrast between the suspect’s uninformed statements and the known facts, providing a strong basis for assessing deception and credibility. Key research can be summarized as follows:
- Granhag & Hartwig (2008): Late disclosure improves lie detection accuracy by allowing interviewers to identify inconsistencies with greater confidence.
- Oleszkiewicz & Watson (2020): Meta-analytic data show late disclosure results in larger deception detection effect sizes than early disclosure, but not as strong as gradual strategies.
- Kelly et al. (2024): Late disclosure can be effective for confrontation but has limitations in eliciting new, detailed information.
Gradual Disclosure: This method involves disclosing available pieces of evidence one by one throughout the interview, requesting the suspect to address each piece in turn often aligned with the suspect’s evolving account. Evidence is introduced incrementally, only when:
- Relevant to an inconsistency,
- Necessary to prompt further clarification, or
- Likely to yield new information or shift a deceptive strategy
This approach offers the interviewer more flexibility and can lead to a wider variety of verbal cues to deception compared to early and late disclosure, potentially improving the veracity of assessments. It is also suggested that a gradual disclosure allows observers to continually update their assessment of the suspect's veracity.
The research noted that this strategy produced the greatest amount of new and previously unknown investigative material. That deception detection is maximized by revealing inconsistencies at key moments. The cognitive load is increased substantially as the interviewee must continually adjust their accounts to disclosures. The feeling of ambush that can accompany the late disclosure of evidence may be tempered by the timing and delivery of relevant disclosures at relevant times.
Overall, Gradual disclosure leverages uncertainty to increase cognitive and psychological pressure. Suspects are unsure how much the interviewer knows, making it harder to sustain a lie or fabricate consistent details. However, the level of interviewer skill and degree of preparation required is higher in this strategy. Key research findings are summarized as follows
- Hartwig, Granhag & Luke (2014): Gradual disclosure is most effective at exposing deceptive strategies and prompting inadvertent admissions.
- Luke & Granhag (2022): The Shift-of-Strategy (SoS)approach—an advanced form of gradual disclosure—yields more critical information than early or late disclosure.
- Kelly et al. (2024): Reinforce that gradual or adaptive evidence disclosure consistently outperforms other methods in both detecting deception and eliciting new details.
Adaptive or Shift of Strategy: The Shift-of-Strategy (SoS) model is a dynamic and adaptive approach to interviewing in which the interviewer strategically introduces evidence to provoke a change in the suspect’s counter-interrogation strategy. It builds on the idea that suspects initially adopt one of several strategies (e.g., outright denial, avoidance) and that effective interviewing can push them toward disclosure or cooperation.
The research noted that this strategy produced an increase in both the quantity and quality of new investigative details previously not disclosed. The verbal cues to deception are enhanced because inconsistencies in the account are generated at critical times, forcing a change in strategy which is very cognitively taxing. The progressive use of disclosures if performed in a supportive non-accusatorial manner can result in more cooperation as the interviewee abandons denial strategies.
Overall, The SoS model turns evidence disclosure into a dynamic psychological maneuver, using each piece of evidence not just to test statements, but to reshape suspect behavior. Key research findings are summarized as follows
- Luke & Granhag (2022):Introduced the SoS model, demonstrating that adaptive evidence disclosure effectively transitions suspects from an avoidance strategy to more disclosure.
- Nyström, Luke & Granhag (2024): Validated SoS over longer interviews; the “Reactive SoS” (responding to inconsistencies) was more effective than “Selective” or direct strategies.
- Kelly et al. (2024): Describe SoS as a promising evolution of the Strategic Use of Evidence (SUE) with superior performance in shifting suspect tactics and eliciting admissions.
The challenge phase of PEACE is best supported by gradual or late evidence disclosure, particularly using techniques developed under the Strategic Use of Evidence (SUE) model. This approach:
- Enhances detection of deception,
- Supports ethical, non-accusatory interviewing, and
- Encourages suspects to reveal new or clarifying information when inconsistencies are revealed.
A future article will examine the practical use of a challenge phase in an interview using the conversation management model contained in the PEACE interview framework.
