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20200524 – Duped – Truth Default




The main idea of this book is to summarize and present author’s decades long research in psychology of lying and methods and tools to recognize lies and obtain truth. In order to do this author presents his Truth Default Theory (TDT) and provides wealth of experimental data supporting this theory. Author also reviews competing theories and ideas and supplies reasons why they do not work.


Chapter 1. The Science of Deception
This chapter starts with author recollection of listening book review of CIA agents on how they recognized lying. From this point he moves to discusses his qualifications as scientific researcher in just this area of psychology and how he came to this. He then present questions that such research supposed to answer:

1. What do people look for in order to distinguish between whether someone else is honest or lying?

2. What, if any, specific behaviors actually distinguish truthful communication from lies?

3. How accurate are people at distinguishing truths from lies?

4. Under what conditions are people more accurate or less accurate at lie detection, and what types of people, if any, are more skilled or less skilled lie detectors?

He also present results of previous research over decades that consistently shown human ability to recognize lies just slightly above random. Here is graph demonstrating these results:

Chapter 2. Cues

This chapter focuses on “cues.” Here is how author describes it:” We will take a close look at the research on:

(a) the behaviors that people think distinguish truths and lies,

(b) the behaviors that people actually rely on in distinguishing truths from lies,

(c) the behaviors that do and do not actually distinguish truths from lies.”

Here is the Summary:

What do people look for in order to distinguish whether someone else is honest or lying? People pay much attention to nonverbal behavior when assessing honesty and deceit. In terms of specific cues, there is a worldwide, cross-cultural consensus in the folk belief that liars avoid eye contact. But when behaviors that actually influence honesty assessments are analyzed, perceptions of plausibility, logical consistency, confidence, friendliness, and conversational involvement are quite important. What’s more, cues are not used in isolation, nor are they uncorrelated. Constellations of cues combine to create an honest or dishonest demeanor that guides people’s decisions about whether or not someone is honest. (There is more on this in chapter 13 when sender demeanor and the BQ [believability quotient] are discussed.)

What, if any, specific behaviors actually distinguish truthful communication from lies? The short answer is, not many. The only two cues that hold up consistently across various meta-analyses are that liars have larger pupils and higher pitch, on average, than honest senders. The differences are not large enough to have much practical use in lie detection. In general, there are few behavioral differences that distinguish truths from lies, and the differences that are there are not large, are inconsistent, and tend to diminish as scientific evidence accumulates.

Chapter 3. Deception Detection Accuracy
In this chapter author “examines people’s ability to distinguish truths from lies in traditional deception detection experiments. In both, priority is given to meta-analysis, looking at trends across larger numbers of studies rather than at the findings of individual studies. I strive to provide a coherent picture of what we know by focusing on findings that reliably replicate and by describing the big-picture implications of those results.”

This chapter answered two important questions:

How accurate are people at distinguishing truths from lies? People are slightly better than chance at distinguishing truths from lies in deception detection experiments. Accuracy is better than chance, but not by much. The across-study average is about 54% correct truth–lie discrimination.

Under what conditions (if any) are people more accurate or less accurate at lie detection, and what types of people (if any) are more skilled or less skilled lie detectors? The slightly-better-than-chance accuracy is remarkably robust and invariant. Some things make a difference of a few percentage points this way or that, but the slightly-better-than-chance holds across a wide range of conditions and methods. Besides answering these two critical questions, this chapter also highlights some important but underappreciated findings. One of these is the small standard errors in deception detection experiments involving multiple judgments per judge. The implication is that even small differences in raw accuracy can be statistically significant with ample effect sizes. Findings need to be understood in context. Second, the number of judgments strongly impacts the results, making unusual results based on small data untrustworthy. Third, raw accuracy (i.e., correct truth–lie discrimination) and accuracy for lies are not the same thing. The implication is that if people are better than chance at truth–lie discrimination, this does not mean that they are better than chance at recognizing lies per se. Finally, there is much more variability in senders than in judges. This suggests that viable explanations for findings need to account for both sender variability and judge constancy.

Chapter 4. Rivals
Here author describes competing theories that preceded his Truth Default Theory.

Author’s Summary: “This chapter provides a chronicle of prior theories of deception and deception detection. Ekman’s original leakage theory, Ekman’s updated perspective, four-factor theory, Bella DePaulo’s self-presentation perspective, Interpersonal Deception Theory, and Aldert Vrij’s cognitive load approach were each reviewed. I see much communality among Ekman, four-factor theory, IDT, and Vrij. In the next chapter, I offer the catchall idea of cue theories as a way to show the commonalities in the logic behind prominent deception theories and to show how theory has shaped research priorities and design. I offer a critical evaluation of these prior theories in specific, and cue theories in general. I hope it is obvious after this chapter why a new theory is so desperately needed.”

Chapter 5. Critiquing the Rivals
This is continuation of the previous chapter where author critiques rivals, their theories and then “provides a detailed rationale for the book and TDT. If prior theory were adequate and sufficient, there would be little to be gained from yet another theory. The case is made that prior theories have serious deficiencies and that the need for TDT is real and pressing.”

At the end of chapter author characterizes his rival as cults and summarizes them in such way:” Various camps of deception researchers have leaders who are revered by followers (e.g., Ekman, Burgoon, Vrij). The members of the various groups are very devoted to the system of beliefs that form the tenets of the various theories, and they see disagreement by outsiders over core issues as heresy. Each of the groups is relatively small in number, and each group sees the doctrines of rival theories as strange, sinister, and threatening. And, at least from my point of view, I think the admiration that the followers of the various theories have for their theories is both excessive and misplaced. Each of the rivals falls short in verisimilitude.”

In this part author moves from critic of rivals to presentation of his Theory

Chapter 6. Truth-Default Theory Summarized
This chapter “provides a succinct and rough summary of TDT. Key definitions are provided. TDT is modular, by which author means that it is an organized collection of stand-alone mini-theories, hypotheses, and effects. Each of the modules is briefly described, and the propositional structure weaving them together laid out. But the chapter just provides an outline, with little explanation.”


TDT is a modular theory. The modules are various minitheories, models, effects, and hypotheses that can stand alone. They can be understood without reference to larger theory. Empirical support or disconfirmation for one module does not imply support or disconfirmation of another module. The modules discussed in the following chapters are:

• A Few Prolific Liars (or “outliars”; chapter 9)—The prevalence of lying is not normally or evenly distributed across the population. Instead, most people lie infrequently. Most people are honest most of time. There are a few people, however, who lie often. Most lies are told by a few prolific liars.

• Deception Motives (chapter 10)—People lie for a reason, but the motives behind truthful and deceptive communication are the same. When the truth is consistent with a person’s goals, he or she will almost always communicate honestly. Deception becomes probable when the truth makes honest communication difficult or inefficient. • The Projected Motive Model (chapter 10)—People know that others lie for a reason and are more likely to suspect deception when they think a person has a reason to lie.

• The Veracity Effect (chapter 12)—The honesty (i.e., veracity) of communication predicts whether the message will be judged correctly. Specifically, honest messages produce higher accuracy than lies. The veracity effect results from truth-bias.

• The Park–Levine Probability Model (chapter 12)—Because honest messages yield higher accuracy than lies (i.e., the veracity effect), the proportion of truths and lies (base-rates) affects accuracy. When people are truth-biased, as the proportion of honest messages increases, so does average detection accuracy. This relationship is linear and is predicted as the accuracy for truths times the proportion of messages that are true plus the accuracy for lies times the proportion of messages that are lies.

• A Few Transparent Liars (chapter 13)—The reason that accuracy in deception detection is above chance in most deception detection experiments is that some small proportion of the population are really bad liars who usually give themselves away. The reason accuracy is not higher is that most people are pretty good liars.

• Sender Honest Demeanor (chapter 13)—There are large individual differences in believability. Some people come off as honest. Other people are doubted more often. These differences in how honest different people seem to be are a function of a combination of eleven different behaviors and impressions that function together to create the BQ (believability quotient). Honest demeanor has little to do with actual honesty, and this explains poor accuracy in deception detection experiments.

• How People Really Detect Lies (chapter 14)—Outside the deception lab, in everyday life, most lies are detected after the fact, based on either confessions or the discovery of some evidence showing that what was said was false. Few lies are detected in real time based only on the passive observation of sender nonverbal behavior.

• Content in Context (chapter 14)—Understanding communication requires listening to what is said and taking that in context. Knowing about the context in which the communication occurs can help detect lies.

• Diagnostic Utility (chapter 14)—Some aspects of communication are more useful than others in detecting deception, and some aspects of communication can be misleading. Diagnostic utility involves prompting and using useful information while avoiding useless and misleading behaviors.

• Correspondence and Coherence (chapter 14)—Correspondence and coherence are two types of consistency information that may be used in deception detection. Correspondence has to do with comparing what is said to known facts and evidence. It is fact-checking. Coherence involves the logical consistency of communication. Generally speaking, correspondence is more useful than coherence in deception detection.

• Question Effects (chapter 14)—Question effects involve asking the right questions to yield diagnostically useful information that improves deception detection accuracy.

• Expert Questioning (chapter 14)—Expertise in deception detection is highly context dependent and involves knowing how to prompt diagnostically useful information rather than passively observing deception cues.

TDT Propositions

The TDT propositions provide a string of assertions, predictions, and conjectures that weave the constructs and modules together to describe and explain human deception and deception detection and to provide coherence. That is, the propositional structure shows how the various modules fit together. The propositions also provide specific, testable, and falsifiable predictions. The propositions are numbered one to fourteen and reflect the logical flow of TDT.

• Proposition one. Most communication by most people is honest most of the time. While deception can and does occur, in comparison to honest messages, deception is relatively infrequent, and outright lies are more infrequent still. In fact, deception must be infrequent to be effective.

• Proposition two. The prevalence of deception is not normally distributed across the population. Most lies are told by a few prolific liars.

• Proposition three. Most people believe most of what is said by most other people most of the time. That is, most people can be said to be truth-biased most of the time. Truth-bias results from, in part, a default cognitive state. The truth-default state is pervasive, but it is not an inescapable cognitive state. Truth-bias and the truth-default are adaptive both for the individual and for the species. They enable efficient communication.

• Proposition four. Because of proposition one, the presumption of honesty specified in proposition three is usually correct. Truth-bias, however, makes people vulnerable to occasional deception.

• Proposition five. Deception is purposive. Absent psychopathology, people lie for a reason. Deception, however, is usually not the ultimate goal, but instead a means to some other ends. That is, deception is typically tactical. Specifically, most people are honest unless the truth thwarts some desired goal or goals. The motives or desired goals achieved through communication are the same for honest and deceptive communications, and deception is reserved for situations where honesty would be ineffectual, inefficient, and/or counterproductive in goal attainment.

• Proposition six. People understand that others’ deception is usually purposive and are more likely to consider a message as potentially or actually deceptive under conditions where the truth may be inconsistent with a communicator’s desired outcomes. That is, people project motive states on others, and this affects suspicion and judgments of honesty and deceit.

• Proposition seven. The truth-default state requires a trigger event to abandon it. Trigger events include but are not limited to: (a) a projected motive for deception, (b) behavioral displays associated with dishonest demeanor, (c) a lack of coherence in message content, (d) a lack of correspondence between communication content and some knowledge of reality, or (e) information from a third party warning of potential deception.

• Proposition eight. If a trigger or set of triggers is sufficiently potent, a threshold is crossed, suspicion is generated, the truth-default is at least temporarily abandoned, the communication is scrutinized, and evidence is cognitively retrieved and/or sought to assess honesty–deceit.

• Proposition nine. Based on information of a variety of types, an evidentiary threshold may be crossed, and a message may be actively judged to be deceptive. The information used to assess honesty and deceit includes but is not limited to: (a) contextualized communication content and motive, (b) sender demeanor, (c) information from third parties, (d) communication coherence, and (e) correspondence information. If the evidentiary threshold for a lie judgment is not crossed, an individual may continue to harbor suspicion or revert to the truth-default. If exculpatory evidence emerges, active judgments of honesty are made.

• Proposition ten. Triggers and deception judgments need not occur at the time of the deception. Many deceptions are suspected and detected well after the fact.

• Proposition eleven. With the exception of a few transparent liars, deception is not accurately detected, at the time in which it occurs, through the passive observation of cues or sender demeanor. Honest-looking and deceptive-looking communication performances are largely independent of actual honesty and deceit for most people and hence usually do not provide diagnostically useful information. Consequently, demeanor-based deception detection is, on average, only slightly better than chance due to a few transparent liars, but typically not much above chance due to the fallible nature of demeanor-based judgments.

• Proposition twelve. In contrast, deception is most accurately detected through either (a) subsequent confession by the deceiver or (b) comparison of the contextualized communication content to some external evidence or preexisting knowledge.

• Proposition thirteen. Both confessions and diagnostically informative communication content can be produced by effective context-sensitive questioning of a potentially deceptive sender. Ill- conceived questioning, however, can backfire and produce below-chance accuracy.

• Proposition fourteen. Expertise in deception detection rests on knowing how to prompt diagnostically useful information, rather than on skill in the passive observation of sender behavior.

Chapter 7. Defining Deception (Beyond BFLs and Conscious Intent)
Chapter 7 takes a close look at issues in defining deception from the TDT perspective. Here is author’s definition of deception, lying, and honest communication:

• Deception is intentionally, knowingly, or purposefully misleading another person.

• A lie (or bald-faced lie, BFL for short) is a subtype of deception that involves outright falsehood, which is consciously known to be false by the teller, and is not signaled as false to the message recipient.

• Honest communication lacks deceptive purpose, intent, or awareness. Honest communication need not be fully accurate or true, or involve full disclosure.

Here author also looks at different types of deception such as self-deception, false statements, and failed deception attempts. He concludes: “An important implication is that message features like the truth and falsity of specific content, message intent, and message function or impact need to be distinguished because these things do not map perfectly onto one another. So, someone can say something that is objectively false, omit information, change the subject, and so forth, in a manner that is either intended to deceive or not. The objective truth or falsity of messages may or may not actually function as deception, and such messages may or may not be perceived as deception. In short, speaker intent, purpose, and message consequence in combination define deception, not the objective qualities of messages or information dimensions (discussed in the next chapter). Further, mere speaker intent is neither sufficient nor necessary in and of itself to define deception.

Chapter 8. Information Manipulation (Beyond BFLs and Conscious Intent, P.2)
Beginning in chapter 8, a series of numbered original empirical studies are summarized testing relevant theoretical predictions. Author discusses in details Information Manipulation theory (IMT) and IMT2, providing review of several relevant studies.

Chapter 9. Prevalence
Chapter 9 explicates TDT’s first two propositions and the Few Prolific Liars module. The empirical support is detailed by reviewing multiple studies. Then author presents his interpretation: “TDT departs from most other theories of deception regarding the prevalence of deception. According to TDT, lying is infrequent relative to the truth. Lying is not normally distributed across the population but is instead highly skewed, with most lies coming from a few prolific liars. And, according to TDT, the frequency of lying matters in deception detection.”

Chapter 10. Deception Motives
In this chapter author examines motivation of people’s lying and delves into proposition five and the People Lie for a Reason module. It provides the first part of the answer to the mystery of accuracy in research that uses deception but is not about deception. Here are key TDT claims regarding motivation:

1. People lie for a reason. That is, deception is purposive. It is therefore not random.

2. Deception is usually not the ultimate goal but instead is a means to some other end or ends. That is, deception is typically tactical.

3. The motives behind truthful and deceptive communication are the same.

4. When the truth is consistent with a person’s goals, the person will almost always communicate honesty.

5. Deception becomes probable when the truth makes honest communication difficult or inefficient.

Then author provides experimental support of these claims.

Chapter 11. Truth-Bias and Truth-Default
Chapter 11 gets to the core of TDT, focusing on truth-bias and the truth-default and summarizing author’s research on them. The existence of the truth-default and the idea of triggers provide additional insight into the mystery of accuracy in research that uses deception but is not about deception. As before author discusses in details experimental results supporting his ideas.

Chapter 12. The Veracity Effect and Truth—Lie Base-Rates
Chapter 12 focuses on two important implications of truth-bias, namely, the veracity effect and the Park–Levine Probability Model. The focus is on the empirical evidence supporting these modules and proposition three. Chapter 12 explains why base-rates are so important. A very important here is that author provides clear falsification criteria and results of its experimental validation:

Chapter 13. Explaining Slightly -Better-than-Chance Accuracy
The focus in chapter 13 shifts to offering a coherent explanation for the prior detection-accuracy findings described in chapters 1 and 3. The companion modules A Few Transparent Liars and Sender Honest Demeanor are explicated, and the evidence consistent with proposition eleven is described. The mystery of normally distributed slightly-better-than-chance accuracy is solved. Here is a very important graphic representation of matched or unmatched demeanor and behavior, which somewhat confuse even professional interrogation experts:

Chapter 14. Improving Accuracy
Here author discusses the ways of improving accuracy. How People Really Detect Lies is described, along with the Content-in-Context, Question Effects, and Expertise modules. In the process, evidence for the twelfth, thirteenth, and fourteenth propositions is provided. Author reviews research documenting five paths to improved lie detection:

• Using evidence to establish ground truth and assessing the correspondence between communication content and ground truth.

• Using situational familiarity and contextualized communication content to assess plausibility.

• Using situational familiarity and contextualized communication content to assess motives for deception.

• Strategically questioning senders to elicit diagnostically useful communication content.

• Persuading liars to be honest and tell the truth.

Chapter 15. The TDT Perspective

This chapter wraps things up, restating key points of TDT and providing 5 keys to improvement in lie detection:

1. Correspondence of communication content with evidence

2. Content in context (situational familiarity)

3. Assessment of deception motives

4. Diagnostic questioning

5. Persuading honesty


This is the great book and I highly appreciate author’s scientific approach to his ideas and TDT’s experimental support. I guess it would allow to skip the whole lot of literature about truth finding via cues analysis. It also nicely demonstrates that I am not alone finding lie to be difficult even when necessary. The findings of this book are also very helpful in design of processes involving human action, making it clear that by removing advantages that could be provided by lying would remove motivation for doing this and consequently its occurrences.  

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