If behavioral cues don’t tell us whether someone’s truthful, what should we be evaluating instead? Stop watching how people behave. Start questioning whether they could actually know what they claim to know.
In my previous article, I recounted that behavioral lie detection doesn’t work — achieving accuracy rates of 52 percent, barely better than chance. After fifty years of research, we cannot reliably detect deception by observing fidgeting, eye contact, or nervous behaviors.
This leaves investigators with a critical question: if behavioral cues don’t tell us whether someone’s truthful, what should we be evaluating instead?
Dr. Christian Meissner, principal investigator for the High-Value Detainee Interrogation Group’s research program, has spent decades researching this question. His answer represents a fundamental reconceptualization of credibility assessment:
This article focuses on the first critical dimension of Meissner’s approach: access. Rather than asking “Do they look nervous?” we should be asking “Could they have actually seen what they say they saw? Heard what they claim they heard? Been positioned to observe what they’re describing?”
The implications are profound and immediately actionable.
Access assessment asks a deceptively simple question: was the person in a position to observe, experience, or learn what they’re claiming?
This isn’t about behavioral observation — it’s about logical evaluation grounded in physics, human perception, and verifiable circumstances. Either someone was positioned to see something, or they weren’t. Either acoustic conditions allowed them to hear, or they didn’t. Either they were present during the relevant timeframe, or they were elsewhere.
Research on workplace investigations identifies access as one of the most reliable credibility factors. Investigators must evaluate whether a witness actually was able to hear or see the conduct they described. Unlike behavioral cues, which are ambiguous and unreliable, access is binary and often verifiable through physical evidence, documentation, or corroborating witnesses.
Consider a witness who claims to have observed a confrontation. Traditional credibility assessment would focus on their demeanor during the interview: do they seem confident? Are they maintaining eye contact? Do they appear truthful?
An access-based assessment asks different questions: where exactly were you standing? What was between you and the confrontation? How far away were you? What were the lighting conditions? How long did you observe? These questions test whether the witness could have observed what they claim, regardless of how confidently they claim it.
The power of access assessment lies in its logical foundation rather than psychological interpretation. Behavioral cues are inherently ambiguous — nervousness could indicate deception, stress, trauma, anxiety, or simply the discomfort of being interviewed. Research has definitively shown that both innocent and guilty individuals experience arousal and stress in interrogative settings, making behavioral responses poor indicators of truthfulness.
But access is different. Access is constrained by:
These constraints make access assessment far more reliable than behavioral observation. When someone claims they saw license plate numbers from 200 feet away in low light, we don’t need to watch their body language — we can evaluate whether human visual acuity makes such observation plausible.
Access assessment requires detailed, strategic questioning about the circumstances under which the person gained the information they’re reporting. This connects directly to interview planning — you must research the incident scene thoroughly enough to ask informed questions about access.
These questions establish the foundational element of access — physical location. Without knowing precisely where someone was positioned, you cannot evaluate what they could observe.
Obstructions dramatically affect access. Someone positioned nearby might have had no effective access if walls, people, or objects blocked sightlines. Conversely, someone farther away with unobstructed views might have had excellent access.
Distance assessment is critical because people regularly overestimate their perceptual capabilities at range. Research on eyewitness identification shows that accuracy degrades significantly with distance, yet witnesses often maintain high confidence regardless of actual viewing conditions.
Lighting dramatically affects visual access. A witness who had perfect positioning and no obstructions might still have had limited access if lighting was poor. Strategic questioning reveals these limitations.
Many investigative interviews involve claims about overheard conversations, sounds, or verbal exchanges. Auditory access assessment requires understanding acoustic conditions and human hearing capabilities.
Research on acoustic perception shows that ambient noise significantly impairs speech comprehension, particularly at distance. Yet witnesses often claim to have heard conversations in environments where acoustic analysis would render such access highly implausible.
The inverse square law dictates that sound intensity decreases with distance. Whispering audible from three feet becomes inaudible at ten feet, yet witnesses sometimes claim to have overheard whispered conversations at implausible distances.
Individual hearing capability varies dramatically, affecting auditory access. Strategic questioning about the witness’s hearing establishes baseline capabilities.
Temporal access — whether someone was present during the relevant timeframe — is often overlooked but critical. People sometimes conflate events from different times, claim observation of sequences they only partially witnessed, or misremember timing.
These questions establish the timeframe of presence. If someone claims to have witnessed events outside this timeframe, their access claim requires explanation.
Physical presence doesn’t equal continuous observation. Someone present in a building might have been in a different room, focused on other tasks, or simply not paying attention. Strategic questioning reveals the difference between claimed and actual observation.
Memory research shows that people regularly misorder events, conflate separate incidents, or fill gaps with assumptions. Detailed timeline questioning reveals whether claimed access to a complete sequence is accurate or reconstructed.
Let me illustrate access assessment with a detailed example.
Initial claim: An employee reports overhearing a supervisor make harassing comments about a colleague in the break room on Tuesday morning.
Traditional approach: Interview the reporting employee, watch for signs of truthfulness or deception, evaluate confidence and demeanor, make a gut judgment about credibility.
Access assessment approach — strategic questions:
Physical positioning: 15 feet away, facing away, with obstructions (table, people).
Auditory conditions: Microwave noise, competing conversation, normal speaking volume.
Actual access: Likely heard fragments at most, but claimed direct access to the full conversation.
Revelation: A significant portion of the “overheard” comments actually came from the coworker’s report.
Outcome: This doesn’t mean harassment didn’t occur — it means this witness’s access was limited. The investigation should interview the coworker who was closer and had better access. Access assessment prevented overreliance on a witness whose actual access didn’t support their claimed observation.
Access assessment integrates seamlessly with other evidence-based approaches:
As I’ve emphasized in previous articles, fewer than one in ten interviews receives adequate planning. Access assessment is impossible without thorough preparation. You must research the incident scene (layout, dimensions, lighting), understand acoustic conditions, know the timeline, identify potential obstructions, and gather evidence that verifies or contradicts access claims. Without this planning, you cannot ask informed questions that test access.
The Cognitive Interview’s context reinstatement technique serves dual purposes: facilitating memory retrieval and revealing access limitations. When you guide someone through detailed context reinstatement, paying attention to what they can and cannot describe reveals their actual access. Rich sensory details about things they should have been able to perceive suggest good access. Vague descriptions or an inability to recall contextual details may indicate limited access or fabrication.
SUE’s emphasis on detecting statement-evidence inconsistencies works powerfully with access assessment. When someone claims access to information that physical evidence — security footage, GPS data, witness corroboration — shows they couldn’t have had, you’ve identified a critical credibility issue. Conversely, when strategic questioning about access reveals someone claims they couldn’t have known something, yet they provide accurate details, this may indicate guilty knowledge.
Moving to access-based credibility assessment requires fundamental shifts:
In Planning: Research the scene extensively. Understand sight lines, distances, acoustics, lighting. Measure spaces. Review photographs and videos. Talk to people familiar with the location. Gather documentation of timelines, entry and exit logs, or other temporal records.
In Questioning: Develop detailed strategic questions about positioning, obstructions, distances, lighting, sounds, timing. Ask “where exactly,” “how far,” “what was between,” “what sounds were present.” Push for specificity that reveals actual access.
In Assessment: Evaluate plausibility based on human perceptual limitations, physics, and environmental factors. Don’t rely on gut feelings about demeanor — rely on logical analysis of whether claimed access is realistic given the circumstances.
In Documentation: Record detailed information about access factors. Document positioning, distances, conditions, timelines. When access supports credibility, note the specific factors. When access limitations exist, document precisely what they are. These are defensible factors; behavioral observations are not.
In Testimony: Explain credibility assessments based on access. “The witness was positioned eight feet away with clear sightlines and good lighting, making observation of the details they described plausible.” Or: “The witness claimed to overhear a conversation from thirty feet away in a crowded, noisy environment, which acoustic analysis suggests is implausible.” Courts understand these explanations. They don’t understand “the witness seemed nervous.”
Access assessment represents a fundamental shift from subjective behavioral interpretation to objective circumstantial evaluation. Instead of watching how someone behaves while making claims, we question whether they could actually have observed what they’re claiming.
This approach is:
Implementing access assessment requires more preparation, more sophisticated questioning, and more rigorous analysis than watching for nervous tics. But it works. And after fifty years of research showing behavioral credibility assessment achieves only chance-level accuracy, we owe it to ourselves and those we serve to adopt approaches that actually function.
Like much of what I write, training is a first step. It is what has moved me beyond my own blind spots, at least some of them. I can provide the training or recommend providers teaching science-based techniques. Do your research, find the right provider, and maximize your training dollar investment. If you are a practitioner or a leader, don’t settle for the same old legacy-based methods that have no empirical evidence supporting them. This is not the time to “do it as we’ve always done it.” If you are in leadership, you carry the same responsibility to know and apply these standards and to find training content that maximizes your team’s effectiveness and accomplishes your mission.
Anderson Investigative Associates is positioned to custom-tailor science-based training to your specific needs. If you have any questions or would like to discuss the subject of this imperative transition, or any training need, please reach out. Additional issues pertaining to interviewing, auditing, and investigations can be found in other blogs and videos that we have produced and are contained in most blocks of instruction that our company presents.
If you have additional questions, comments, or an interview topic you would like me to address, just let me know. In the meantime, be well, stay safe out there, and start investing in a transition that is ethical and effective. It will improve everything you do. It’s time to improve your interviewing and communication skills, not only in your work, but throughout your life. If you need help getting ready, I know who could help.
In my next article, I’ll explore the second dimension of Meissner’s framework: knowledgeability — assessing whether witnesses possess the expertise and understanding necessary to accurately report and interpret what they claim to have observed.
Read the previous article: “The End of Behavioral Lie Detection: What 50 Years of Research Actually Shows”
Coming next: “Assessing Knowledgeability: Testing Expertise and Understanding”