Interpersonal Deceptive Practices

There is a long and robust record of scientific investigation into detecting interpersonal deception.

RAND Project sponsored by CIA Behavioral Sciences Staff
Scott Gerwehr, Principle Investigator


There is a long and robust record of scientific investigation into detecting interpersonal deception (highlights include De Paulo et al, 2003; Vrij, 2000; Zuckerman et al, 1981; Ekman & Friesen, 1969). This work has included both content-analytic approaches (what information is being communicated) as well as behavior-analytic approaches (how the information is being communicated), and usually focuses upon detecting lies (as opposed to detecting omissions or obfuscation). However, despite the significant amount of scientific work on detecting deception, there is astonishingly little on conducting interpersonal deception. What are the most effective methods for deceiving? What are the key personal and environmental variables for success or failure? What factors shorten/prolong or amplify the effect of deception? Although such questions are entirely amenable to empirical investigation, they have largely remained unasked in a scientific setting. Those professions or vocations that feature interpersonal deception as a central component of the job (e.g., undercover police work) frequently have little written doctrine on how to deceive, and even more rarely have subjected that doctrine to rigorous scientific inquiry. This project aims to 1) systematically comb through the existing scientific literature for guidance on effectively practicing interpersonal deception, 2) survey a wide-variety of professionals who practice deception, in order to compile a broad knowledge base containing "best practices" of conducting deception, 3) identify gaps or untested hypotheses regarding the practice of deception in both the scientific literature and professional knowledge base, and 4) formulate a "road map" of scientific experimentation to address shortcomings, inaccuracies, and gaps in existing doctrine on deceiving.

In the literature review we will be looking for doctrinal principles regarding interpersonal deception; in the interview and survey process, we will be seeking information about expert prototypes. It is an important conceptual point to note the difference between these two sources of wisdom:

Prototypes, first proposed by Rosch (1975) and explored by Aron & Westbay (1996) and others in interpersonal relations work, treat expertise/knowledge as instantiated in a model (the prototype), and that model is exemplary (usually the product of experience and evolution). In the case of Aron & Westbay's work, for example, they investigated individual concepts of love as prototypical, that is to say that individuals decide whether they "love someone" or "are in love" by referring to the exemplar in their minds, not a dictionary definition. Individuals who professionally practice deception (e.g., smugglers, undercover cops) may have a great deal of explicit and implicit information about what variables are key, what methods work and don't work, but it helps to understand that their expertise is a prototype. It is very real and very effective, but a direct evolutionary result of the context within which it developed.

Doctrinal knowledge/expertise stems from a canonical definition, usually generated by experiments and study. A very few experiments have instrumented the deceiver and studied various types of lying to see which is most effective in a particular circumstance, for example. That said, we may be able to glean important hypotheses from reversing the findings of detection studies (e.g., if appearing tense and giving a negative impression can be cues to deception, then we may hypothesize that deception will be more easily accomplished if one can appear relaxed and likeable).

Sample Survey/Interview Questions

For effective interpersonal deception there may be some generalities common to a number of fields (e.g., acting, undercover work, smuggling, unscrupulous sales or con artistry). In your opinion, for effective interpersonal deception:

  • What, if anything, do you need to know ahead of time about the audience?

  • How do you find out the critical information about the audience?

  • What audience traits/states are "showstoppers"?

  • Does it matter to you how many audience members there are?

  • What aspects of the milieu would you like to control?

  • What milieu features are "showstoppers"?

  • What milieu features do you capitalize on?

  • How much time is the appropriate amount of time to effectively deceive? Would you rather have more time or less time in any given situation (i.e., operate more or less quickly than the "usual")? If the answer is "it depends", then depends on what?

  • What are the critical variables about yourself necessary to ensure deception?

  • What do you do/not do with your: Hands? Eyes? Posture? ...?

  • What, if anything, is it important to keep in mind while deceiving? Objective? Story? Character?

  • How important is the style or tone of your speaking?

  • How important is the actual content?

  • How do construct the narrative? What are the key choices you have to make?

  • What is the right mix of truth, falsehood, and omission? How does this change with the objective?Audience? Environment?

  • Does the deception have to be perfect to be effective? What % is enough?