Interest in the ability to detect deception has characterized humankind for centuries. Despite both systematic and serendipitous advances in decep- tion detection, however, a foolproof method still eludes us. A large part of the reason is that researchers have not yet identified a profile of the decep- tion experience—a set of mental, emotional, physiological, and/or behav- ioral activities—that characterizes deceptive communicators without fail.
Despite the lack of a foolproof method of deception detection, research has illuminated a number of markers that typically characterize deceivers. In this section, we address the cognitive, emotional, and physiological activ- ities that senders tend to experience when attempting to deceive others. As we addressed above, however, the extent to which these experiences ac- company deception is likely related to the level of social disapproval that the deceptive act would elicit. Thus, they should be more pronounced for acts of perjury, for example, than for acts of politeness. Our discussion here also presumes that senders are possessed of normal emotional and cogni- tive faculties. In cases of psychopathology, for example, senders may not appreciate the difference between deceiving and truthtelling, nor be aware of when they are deceiving. In such instances, senders are unlikely to ex-
hibit the cognitive, emotional, and physiological correlates of deception that characterize the normal adult population.
One of the earliest theoretic treatments of deception was Ekman and Friesen’s (1969a) leakage hypothesis. The hypothesis was grounded in the idea that deception is an emotionally charged activity that is accompanied by physiological arousal on the part of the deceiver. Physiological arousal produces outcomes such as increased perspiration, increased muscular ac- tivity (e.g., shaking and fidgeting), pupil dilation, and vocal tension, that leak out of the body through channels that the deceiver tends to ignore. For instance, deceivers may focus on their verbal message, their eye contact, and their facial expressions during a deceptive interaction, while simulta- neously forgetting about other nonverbal channels such as their kinesics or vocalics. Their deception-induced arousal may, therefore, leak out of their bodies through extraneous hand movement (such as fidgeting or excessive gesturing) or through vocalic cues (such as increased modal pitch or vocal tension).
Other outcomes of arousal leak out of the body through channels that the deceiver simply cannot control—perspiration or pupil dilation, for in- stance. In either case, these leakage cues can give deceivers away, despite deceivers’ best efforts to control their presentations. Recognizing that some channels of nonverbal communication are more controlled or con- trollable than others, Ekman and Friesen predicted that leakage cues con- veyed through the least controlled or controllable channels would be the most accurate and reliable indicators of deception.
The leakage hypothesis suggested to researchers that, in terms of non- verbal behaviors, they should focus on those channels that are not typi- cally controlled (rather than those that are) for cues to deception. What mental, emotional, physiological, and/or behavioral activities, in particular, are relevant to the detection of deception? Zuckerman, DePaulo, and Rosen- thal (1981, 1986) provided an answer in their four-factor theory. This theory offers that four specific internal processes tend to accompany deceptive be- haviors. The first is physiological arousal, which includes the nervous sys- tem outcomes implicated in the leakage hypothesis (such as perspiration, pupil dilation, etc.). The second is the deceiver’s own emotional reaction to his or her guilt at deceiving and/or fear of getting caught deceiving. The third process is the increased cognitive effort required to formulate a plau- sible deceptive message. The final process is the deceiver’s attempted con- trol of his or her presentation of the deceptive message so as to maximize its plausibility and suppress cues to the deception. An important notion that Zuckerman et al. carried over from the leakage hypothesis is that these cues are hierarchical in terms of their controllability, such that some (e.g., eye contact) are more controllable than others (e.g., pupil dilation). We dis- cuss each of these characteristics in greater detail below.
Physiological Arousal
People’s attempts to deceive are often accompanied by some level of heightened physiological arousal, which tends to manifest itself in in- creased activity of the autonomic nervous system (Podlesny & Raskin, 1977; Waid & Orne, 1981). Research in polygraphy (and psychophysiology in gen- eral) has offered much in the way of understanding about the physiological arousal that accompanies deception. The polygraph test, as it is used to- day, can trace its roots to Harvard psychologist William Marston, who re- ported in 1917 that systolic blood pressure (the pressure exerted against the walls of the arteries when the heart contracts) rose when test subjects were being deceptive. He eventually introduced the lie detector test (Mar- ston, 1938), and its results were used in a now famous case involving ac- cused murderer James Frye, who attempted to introduce as evidence the fact that Marston’s blood pressure test indicated he was being honest in his denial of the crime. In Frye v. United States (293 F.1013 1924), which would become a landmark test case, the U.S. Supreme Court ruled that the results of such lie detector tests are inadmissible as evidence in criminal trials.
Despite this, however, research on the physiological reactions associ- ated with lying has flourished. Indeed, Iacono (2000) noted that the study of deception has been the “most prevalent application of a psychophysio- logical technique” as research on polygraphy has evolved over the last 75 years (p. 772). The modern polygraph machine measures three types of psychophysiological indicators of the arousal associated with deception: (1) electrodermal activity, which is measured as either skin conductance or resistance of electrical current; (2) pneumatic activity, which is the rate of respiration; and, (3) cardio activity, including heart rate and relative blood pressure (Iacono, 2000).
Of course, the important question for researchers and practitioners of polygraphy is whether these physiological markers are valid indicators of deception. This is far from a trivial question because, as several research- ers have noted, there is no known physiological response that is unique to deception (see Andreassi, 2000). This means that the electrodermal, pneu- matic, or cardio arousal measured in polygraphy as indicators of lying could occur for reasons entirely unrelated to the truthfulness of a person’s statements (see Furedy & Ben-Shakar, 1991; Furedy, Davis, & Gurevich, 1988; Saxe, 1991). However, experiments conducted both in laboratory and field settings have indicated that polygraph-aided interrogations tend to pro- duce substantially higher than average accuracy in deception detection (e.g., Forman & McCauley, 1986; Kircher, Horowitz, & Raskin, 1988; Patrick & Iacono, 1989, 1991). Of all of the physiological activities measured in poly- graphy, electrodermal activity (in the form of skin conductance) has been found to be the most accurate predictor of deception in both field research
(Barland, 1975) and laboratory experimentation (Cutrow, Parks, Lucas, & Thomas, 1972; Thackray & Orne, 1968).
As one might anticipate, polygraph accuracy rates tend to vary accord- ing to the technique used by the interrogator (see Ginton, Daie, Elaad, & Ben-Shakar, 1982; Gustafson & Orne, 1964; Horvath & Reid, 1971; for review, see Iacono, 2000); however, research has consistently indicated high reli- ability (³ .80) among interrogators in their interpretations of polygraph re- sults (see Horvath, 1977; Patrick & Iacono, 1991).
Two important caveats about the relationship between deception and arousal are worth explicating. First, as we alluded to above, a number of studies have demonstrated that the level of physiological arousal accompa- nying a deceptive act varies according to the seriousness of the lie (and the gravity of the consequences if the lie is discovered), the sender’s motiva- tion to succeed in deception, and the sender’s ability to rehearse the lie be- forehand (see Knapp & Comadena, 1979; O’Hair, Cody, & McLaughlin, 1981; Zuckerman & Driver, 1985). As a result, every deceptive act will not produce the same level of arousal; lying in court while under oath should be ex- pected to produce greater arousal than telling a little white lie to spare a friend’s feelings, because the former lie is more serious and carries more grave consequences if discovered. Lies told under conditions of low arousal may be particularly difficult to detect, therefore.
Second, as Buller and Burgoon (1994) noted, although deception is often accompanied by arousal, arousal is not always accompanied by deception. In other words, overt signs of arousal—such as vocal stress, more speech errors and hesitations, pupil dilation, and increased blinking—do not neces- sarily indicate that deception is occurring. It is important to keep in mind that physiological arousal is the body’s way of increasing the energy pro- duction necessary to meet a perceived challenge, and communicators rou- tinely face a number of challenges other than deception (see Berntson, Boysen, & Cacioppo, 1992). For example, people may exhibit signs of in- creased arousal during conversations because of emotional experiences, such as passion or anger, or because of internal physical states that have nothing to do with the conversation itself. In other words, arousal operates to maintain a necessary level of energy in the body—not to help communi- cators detect deception; although arousal often accompanies deceptive acts, it is not necessarily evidence of them.
Negative Affect
Physiological arousal is, in and of itself, affectively neutral. When it is ac- companied by positive affect, such as joy, people experience arousal as ex- citement or exhilaration. The act of deceiving, however, is often accompa- nied by at least two negative emotions: fear of being caught and guilt for
being deceptive in the first place (see Ekman & Friesen, 1969a, 1974; Zuckerman et al., 1981). When physiological arousal is accompanied by neg- ative affect, people experience the arousal not as excitement but as anxiety or stress. The presence of negative affect, therefore, can serve as another clue to the presence of deception.
The evidence that people experience negative affect when deceiving comes from research on the verbal and nonverbal correlates of deception. For instance, Knapp, Hart, and Dennis (1974) reported that, compared to truthtellers, deceivers made more disparaging remarks and used fewer in- clusive references, such as references to a group. In their meta-analyses, Zuckerman and Driver (1985) and Zuckerman et al. (1981) both found that people use a greater number of negative statements when lying than when being truthful.
Nonverbal behaviors tend to follow a similar pattern. For instance, liars appear to have more negative affect in their tone of voice than do truth- tellers (Buller & Aune, 1987). Likewise, Ekman, Friesen, and O’Sullivan (1988, 1997) indicated that deceivers may use fewer genuine smiles (as opposed to staged smiles) than truthtellers. Some studies have also reported that de- ceivers reduce their eye contact (Knapp et al., 1974), although the evidence on this is mixed. We describe the nonverbal behavioral correlates of decep- tion in greater detail later.
Attempted Control
To avoid detection successfully, deceivers must attempt to control any- thing in their lies, or in their presentation of them, that would give them away. Paradoxically, however, deceivers’ attempts to control their behav- iors can backfire, making their deception more transparent. For example, deceivers may exert excessive control over their behaviors, making their performance appear rigid, insincere, and lacking in spontaneity (see Greene, O’Hair, Cody, & Yen, 1985; Knapp et al., 1974). In addition, because some nonverbal channels are easier to control than others—and because some cannot be completely controlled—deceivers are often unable to exert consistent control over all of their behaviors, resulting in discrepancies among nonverbal channels. For instance, verbal and facial cues might pre- sent one story, while vocalic and kinesic cues portray a different story en- tirely (Zuckerman et al., 1981).
Deception researchers have identified three separate but interrelated types of control that communicators exercise in the service of deception success. The first is information management, or control over the content of the lie itself. This task begins with the formulation of a plausible story. By way of example, let us suppose that David is going to lie to Erin, his boss, about why he must miss school the following Friday. He may start by fash-
ioning a story that he thinks Erin will believe (e.g., his grandfather died and he must attend the funeral). In crafting his deceptive message, however, Da- vid must attend to a number of other issues. One such issue is how much detail he wishes to offer. Deceivers often provide less detail than truth- tellers about the same type of story, presumably because deceivers do not have the same level of detail at their disposal. A strategic move, then, might be for David to craft his story with a sufficient amount of detail to give the appearance he is not being vague or equivocal. In so doing, though, he must take care to ensure that any detail he adds to his story will not contradict what Erin already knows to be true (which, given the small town in which David lives and works, may be a substantial amount of information). In fact, David may choose to incorporate details into his story that are actually true, so as to preempt her suspicion. He must also try to anticipate Erin’s questions and formulate answers for those. Of course, his answers must be every bit as credible as the story itself if David is to be successful in his de- ception attempt.
A second type of attempted control is behavior management, which re- fers to deceivers’ attempts to control their communicative behavior so as to prevent detection. Hocking and Leathers (1980) suggested that deceivers try to control those behaviors that they stereotypically associate with decep- tion. For example, they may concentrate on maintaining eye contact and re- ducing overt signs of nervousness if they believe those behaviors to be cues to deception. The four-factor theory by Zuckerman et al. (1981) suggests, however, that these very attempts at controlling one’s behavior can backfire, inadvertently leading to other leakage behaviors that belie one’s intentions.
Part of behavior management is one’s decision about how to communi- cate the lie. This is largely a decision about channel richness, or how many channels of information a deceiver wishes the recipient to have. For in- stance, David could tell Erin about his grandfather’s funeral in a channel- rich context, such as a face-to-face conversation. In this context, Erin has access to the visual channel (giving her the ability to observe David’s be- haviors), the verbal channel (giving her the ability to scrutinize his mes- sage), and the vocal channel (giving her the ability to ascertain any ner- vousness or disfluencies in his voice), and she is interacting with David in real (synchronous) time, so she can make judgments about David’s perfor- mance as it is happening. By contrast, David could choose leaner contexts, such as talking to Erin on the phone (synchronous access to verbal and vo- cal channels only), leaving her a voicemail message (asynchronous access to verbal and vocal channels), doing an online chat with Erin (synchronous access to verbal channel only), or writing her a note or e-mail message (asynchronous access to verbal channel).
Both channel richness and synchronicity can be implicated in deceivers’ attempted control. Asynchronous, channel-lean contexts, such as writing a
note or e-mail message, provide senders with maximal control over the ver- bal message. They allow for careful crafting of the words and phrases and provide the ability to entertain several drafts of a message before transmit- ting the desired one. However, this control over the verbal message comes at the expense of two other abilities: the ability to use one’s nonverbal be- haviors to enhance the credibility of the message, and the ability to per- ceive and respond to suspicion. In a synchronous, channel-rich context, such as a face-to-face conversation, skilled deceivers can use their facial, ki- nesic, and vocalic behaviors to enhance the believability of their messages (by, for instance, appearing to speak and behave exactly as they normally would in the same circumstances). They also have the ability to ascertain, on the basis of receivers’ own facial, kinesic, or vocalic behaviors, whether receivers are suspicious of the message—and if so, they can engage in repair behaviors to reduce receivers’ suspicions. Of course, these abilities may come at the expense of control over the verbal message (which may not be delivered aloud with the same precision as if delivered in writing), and they also give receivers the ability to ascertain leakage cues—an ability they gradually lose as channel richness decreases. We will address the effects of interactivity on the ability to detect deception later in this chapter.
A third type of attempted control is image management, or deceivers’ at- tempts to appear credible and trustworthy to recipients. Of course, people are always managing their images (cf. Goffman, 1959). Within the context of deception, however, image management refers specifically to behaviors un- dertaken by senders to protect their images during a deceptive behavior. DePaulo, Stone, and Lassiter (1985b) posited that image management is a major objective of deceivers and that it will prompt behaviors that are in- tended both to maintain pleasantness (e.g., smiling, backchanneling) and to deflect attention away from the deceiver. Concerns over relationship man- agement are often intertwined with image management motivations. When deception occurs within ongoing relationships, whether romantic, platonic, familial, or professional, deceivers may strive to manage their images for the purpose of managing, and preventing damage to their relationship with the receivers. As Buller and Burgoon (1994) noted, however, experimental evidence for image and relationship management behavior has been mixed, warranting caution when drawing generalizations about what receivers do to protect their images.
Cognitive Strain
The fourth factor in the theory by Zuckerman et al. recognizes that, in gen- eral, creating a lie is a more demanding task than telling the truth. To be suc- cessful, deceivers must attend to multiple issues, many simultaneously. If the lie is planned, deceivers must begin by crafting plausible messages that are logically consistent and that do not contradict other information that receiv-
ers may already have. They must also anticipate potential questions and craft responses; such responses must also be logical and consistent with re- ceivers’ knowledge. Deceivers must decide on the modality for conveying the lie. If they convey it in a real-time interaction (such as face-to-face or via tele- phone), they must also attend to receivers for potential suspicion cues and, if they perceive suspicion, they must engage in conversational repair behav- iors to mitigate that suspicion. In addition, they must be aware of their own behaviors in order to minimize leakage cues (see, e.g., Buller & Burgoon, 1996; Gilbert, Pelham, & Krull, 1988; Zuckerman et al., 1981).
Attending to all of these demands can strain people’s cognitive re- sources, such that deceiving is a more cognitively demanding activity than is truthtelling. As Mark Twain opined in his 1894 Notebook, “If you tell the truth, you don’t have to remember anything.” The cognitive demands of de- ception are important not only because they require an adequate intellec-