A General Perspective on Deception

Lying appears to be a universal behavior that has been morally condemned across cultures and historical periods. Liars have been consistently portrayed as morally reprehensible, sinful, or socially corrosive. Yet despite this generalized moral condemnation, deception is a common feature of everyday social interaction. Most individuals have lied at some point in their lives, yet most do not lie frequently, underscoring the importance of distinguishing between lying as a common human behavior and lying as a problematic trait.

From a developmental perspective, lying emerges early in childhood. Research suggests that children begin to engage in deception around the age of two or three, coinciding with the development of the theory of mind and executive functioning (Lee, 2000). If the mere occurrence of lying were sufficient to label someone a liar, virtually all individuals beyond early childhood would qualify. However, common usage of the term “liar” tends to be reserved for individuals who lie with unusual frequency or whose lies are judged to be particularly serious.

Intent is a central feature in most scholarly definitions of lying. Lying is typically defined not merely as saying something false but as knowingly attempting to mislead another person. For example, Ekman (1985) defined lying as a deliberate attempt to mislead another person without prior notice. Similarly, Vrij (2000) emphasized the deliberate creation of a false belief, regardless of whether the attempt succeeds. Livingston Smith (2004) broadened this conception to include any behavior whose function is to provide false information or deprive others of true information. More recent formulations converge on three core elements: 1) the manipulation of communicative signals (usually language), 2) the belief that the communicated content is false, and 3) the intention to mislead another person (Hart, 2019; Curtis & Hart, 2023). These definitions collectively distinguish lying from mistakes, misunderstandings, irony, or fictional storytelling, where no intent to deceive is present.

Although lying is often treated as a unitary phenomenon, people lie for a wide variety of reasons. Empirical work suggests that most lies are motivated by relatively mundane concerns rather than malicious intent. Common motivations include avoiding punishment, preventing embarrassment, protecting oneself or others, managing social awkwardness, maintaining privacy, and influencing others’ behavior (Ekman, 2021). Other taxonomies distinguish between self-serving and other-oriented lies, or between lies told for material gain versus psychological benefit (Vrij, 2008). Importantly, the majority of people are honest most of the time, and deception tends to be situational rather than habitual.

Demographic variables have been examined in relation to deceptive behavior, though findings are often modest and context-dependent. Gender differences, for example, are small but recurrent. Large-scale meta-analytic work suggests that men are slightly more dishonest than women overall, though the effect size is limited (Gerlach et al., 2019). However, when focusing specifically on high-frequency liars, men appear to be disproportionately represented (Hart et al., 2022). Research further suggests qualitative differences in deception: women are more likely to tell altruistic or prosocial lies, whereas men more often engage in self-serving deception that imposes costs on others. Age is another important factor. Lying frequency tends to increase rapidly in early childhood, peak during adolescence, and gradually decline throughout adulthood, likely because of developmental changes in autonomy, moral reasoning, and impulse control.

Moreover, personality has long been assumed to play a central role in honesty and dishonesty. Intuitively, it is appealing to believe that some people are fundamentally honest while others are inherently deceptive. However, situational factors appear to exert a stronger influence on deceptive behavior than stable personality traits. Opportunity, perceived norms, and contextual pressures can substantially shape whether individuals choose to lie. 

Despite its prevalence, lying carries significant social costs. People generally dislike being lied to and view deception as a betrayal of trust. Lying erodes interpersonal relationships, undermines intimacy, and reduces overall relationship satisfaction. In occupational and social contexts, habitual liars are more likely to face reprimands, dismissal, or social exclusion. At a societal level, deception threatens the trust that underpins social cooperation. Nevertheless, it is important to recognize that not all frequent liars are motivated by malice or conscious exploitation. In some cases, excessive lying may reflect underlying psychological distress rather than deliberate manipulation—a distinction that becomes crucial when considering pathological forms of deception.

What Is Pathological Lying?

Despite a long history of clinical observation and scholarly discussion, pathological lying remains poorly defined and inconsistently recognized within psychology and psychiatry. Although clinicians have described individuals who engage in pervasive, excessive, and seemingly purposeless lying for more than a century, pathological lying has not been formally recognized as a distinct diagnostic category in major classification systems. As a result, individuals who suffer from chronic lying behaviors often receive alternative diagnoses or none at all, limiting access to appropriate conceptualization and treatment (Curtis & Hart, 2023).

Historically, pathological lying has been referred to by several overlapping terms, including compulsive lying, habitual lying, and pseudologia fantastica. The American Psychological Association defines pseudologia fantastica as a clinical syndrome characterized by elaborate fabrications typically produced to impress others, escape awkward situations, or enhance self-esteem (APA, 2020). These fabrications are usually abandoned when confronted with contradictory evidence and are distinguished from delusions in that the individual does not hold them with fixed conviction. Although pseudologia fantastica has often been associated with antisocial personality disorder, factitious disorder, malingering, and certain psychotic conditions, it has also been observed in individuals who do not meet criteria for these diagnoses.

One of the earliest systematic clinical descriptions of pathological lying was provided by Healy and Healy (1915). They characterized pathological lying as falsification that is grossly disproportionate to any discernible external goal and persists over long periods, often spanning years or a lifetime. Importantly, they emphasized that pathological lying is a stable trait rather than a transient episode and occurs in individuals who cannot be readily classified as psychotic, intellectually disabled, or neurologically impaired. Healy and Healy also highlighted the complexity and imaginative richness of the lies, noting that these fabrications often involve extensive narratives rather than isolated falsehoods.

Subsequent authors have attempted to refine and operationalize this construct. Ford (1996) described pathological lying as a compulsive or impulsive pattern of deception that occurs regularly and often lacks clear material benefit. In some cases, the behavior appears self-defeating, resulting in social, occupational, or legal consequences that outweigh any apparent gains. 

Treanor (2012) described pathological lying as the habitual production of extensive, often fantastical falsifications that are disproportionate to any discernible external purpose. According to this view, pathological lies are not primarily motivated by tangible rewards such as money, status, or avoidance of punishment. Instead, unconscious psychological motivations—such as self-esteem regulation, narcissistic gratification, wish fulfillment, or defensive processes—are thought to predominate.

More recently, Curtis and Hart have proposed a formal conceptualization of pathological lying grounded in empirical research (Curtis & Hart, 2020; Curtis & Hart, 2023). They define pathological lying as a persistent and pervasive pattern of excessive lying that results in clinically significant impairment or distress across social, occupational, or other important domains of functioning. They proposed diagnostic criteria similar to those used in the DSM system. According to these authors, to diagnose pathological lying, the behavior must persist for at least six months, cannot be attributed to substance use or medical conditions, and is not better explained by another mental disorder, such as antisocial personality disorder, psychopathy, or delusional disorder. This framework distinguishes between primary pathological lying, in which deception spans a wide range of topics, and secondary forms, in which lying is closely linked to another condition or serves a more circumscribed function, such as in factitious disorder.

A key feature across historical and contemporary accounts is that individuals who lie pathologically often suffer as a result of their behavior. Excessive lying damages relationships, undermines trust, disrupts occupational functioning, and often leads to social isolation. Many individuals report distress, shame, guilt, and a sense of helplessness about their inability to stop lying. Contrary to stereotypes of liars as manipulative or callous, pathological liars may experience their behavior as ego-dystonic and difficult to control. Most importantly, as Curtis and Hart (2023) indicate, pathological lying must not be confounded with psychopathy. 

Reviews of clinical case material further reveal recurring phenomenological patterns. Treanor (2012) found that in pathological lying, the deceptive behavior persists over many years, is largely unmotivated by external gain, and individuals are generally aware that they are lying. Furthermore, the lies typically involve events that are possible but implausible, and their content is often self-aggrandizing or frames the individual as a hero or a victim. Healy and Healy (1915) remarked that, over time, the liar may lose volitional control over the behavior.

Findings in the (Neuro)Scientific Literature

Interest in the neurobiological underpinnings of deception has grown substantially over the past several decades, driven by advances in neuroimaging and cognitive neuroscience. Although most of this research has focused on deception in general rather than pathological lying specifically, a smaller body of clinical and neuroimaging studies has sought to identify structural and functional brain differences associated with excessive or compulsive lying. Together, these findings suggest that pathological lying may be linked to atypical functioning in neural systems supporting executive control, working memory, impulse regulation, and socioemotional processing. However, the literature remains limited and must be interpreted with caution.

One of the earliest neuroimaging investigations specifically addressing pathological lying was conducted by Modell and colleagues (1992), who studied a 35-year-old man who self-identified as a pathological liar and whose behavior significantly impaired his social and occupational functioning. The authors found that, in addition to the frontal regions of the brain, subcortical structures may also play a role in pathological deception.

Subsequent work shifted attention to the prefrontal cortex, a region critically involved in executive functioning, behavioral regulation, and complex decision-making. Yang and colleagues (2005) compared prefrontal brain volumes in individuals identified as pathological liars, antisocial controls, and healthy controls. They found that the liar group exhibited a substantial increase in prefrontal white matter compared with the other two groups. At the same time, the liars showed a marginal reduction in prefrontal gray matter relative to healthy controls. The authors proposed that increased white matter connectivity may enhance cognitive capacities relevant to deception, such as planning, information manipulation, and response inhibition, thereby facilitating more frequent or fluent lying.

These findings were partially replicated in subsequent work by the same group of researchers. Individuals classified as liars showed increased white matter volume in the inferior, middle, and orbitofrontal cortices compared with both antisocial and healthy control groups, whereas no significant gray matter differences were observed (Yang et al., 2007). The consistency of white matter findings across studies suggested a possible neurodevelopmental contribution to pathological lying, although the direction of causality remained unresolved. Without longitudinal data, it is unclear whether atypical brain structure predisposes individuals to pathological lying or whether chronic engagement in deception leads to neuroplastic changes over time. This ambiguity has been repeatedly noted by researchers and remains one of the central unresolved questions in the field.

Beyond structural imaging, functional neuroimaging studies of deception have shed light on the brain dynamics underlying lying. A review of the scientific literature found that deception was consistently associated with activation in brain regions implicated in working memory, cognitive control, conflict monitoring, response inhibition, and goal integration (Abe, 2011), processes essential for constructing and maintaining deceptive responses. Abe emphasized that deception is not supported by a single, dedicated neural module but rather emerges from the interaction of multiple cognitive systems.

These findings suggest that individuals who lie compulsively have a different way of processing information due to structural and functional brain characteristics.

Case studies of neurological disorders provide additional support for a neurocognitive model of pathological lying. Poletti and colleagues (2011) described pathological lying as a symptom in a patient with behavioral-variant frontotemporal dementia, a condition characterized by executive dysfunction, impaired social cognition, and altered personality. Neuropsychological testing revealed deficits in executive functioning and theory of mind, reinforcing the view that impairments in self-monitoring and social cognition may increase susceptibility to excessive or inappropriate deception.

More recent work has extended these findings to adolescent populations. Curtis, Hart, and Talwar (2025) reported that adolescents identified as pathological liars exhibited clinically significant deficits in executive functioning, particularly in working memory, attention regulation, and impulse control. Notably, these deficits were more pronounced than emotional or conduct-related problems, suggesting that pathological lying may be more closely tied to cognitive control failures than to antisocial traits. Participants reported lying impulsively to reduce anxiety in social situations, often without considering long-term consequences.

Although these findings are promising in advancing understanding of the biological underpinnings of pathological lying, the evidence remains largely preliminary. Small sample sizes, heterogeneous definitions, reliance on cross-sectional designs, and the difficulty of modeling real-world deception in laboratory settings all limit conclusions. Further longitudinal and multimethod research will be essential to clarify causality, developmental trajectories, and clinical implications.

Reports of Cases in the Scientific Literature

One of the earliest comprehensive discussions of pathological lying was provided by Risch (1908), later translated and expanded upon by Healy and Healy (1915). Risch observed that pathological liars appeared to construct their falsehoods in a manner resembling fiction writers, weaving elaborate, imaginative narratives. In Risch’s cases, patients recounted dramatic adventures, dangerous escapes, and romantic exploits, all of which were entirely fabricated yet presented with conviction and emotional investment. These lies appeared to serve an internal psychological function rather than an instrumental purpose.

Healy and Healy (1915) described multiple cases. For instance, Inez produced falsehoods effortlessly and spontaneously, even while acknowledging her tendency to lie. Objective testing revealed intact perception and memory; her unreliability emerged primarily when her self-image or personal significance was involved. Her lies often served to maintain a particular self-presentation, and she frequently lied to cover previous fabrications, creating an expanding web of deception.

Deutsch (1922/1982) described pathological lies as having a “daydream quality.” She argued that while most individuals privately entertain fantasies of heroism, success, or admiration, pathological liars externalize these fantasies, presenting them to others as lived reality. In this sense, pathological lying blurs the boundary between imagination and social communication without fully collapsing into psychosis.

Wiersma (1933) reported the case of a young adult man who told elaborate stories about aristocratic friendships, royal acquaintances, and life in foreign castles. Although these narratives were implausible, the patient occasionally acknowledged their fictional nature and did not appear delusional. Wiersma concluded that the patient lied not to exploit others but because he was emotionally captivated by his own stories and derived intrinsic satisfaction from telling them. 

Curtis and Hart (2023) reported two contemporary, previously unpublished cases that illustrate the persistence and thematic consistency of pathological lying over time. Mr. L engaged in highly embellished, fantastical storytelling, frequently portraying himself as extraordinarily brave, sexually successful, or fortunate. His accounts included physically impossible feats and repeated scenarios in which he narrowly escaped harm. Mr. D, by contrast, produced lies that were superficially plausible but internally inconsistent. He repeatedly claimed military service, severe injuries, paralysis, and terminal illness, yet failed to provide corroborating details and altered his stories upon retelling. In both cases, the lies cast the individual as either a heroic figure or a victim of extraordinary circumstances, and both men experienced significant relational and occupational impairment.

Frierson and Joshi (2018) described a male defendant whose life history was dominated by improbable and demonstrably false claims, including kidnapping by drug cartels, elite military service, and exceptional academic achievement. Collateral information from family members indicated that these narratives were fabricated. The authors noted that the patient did not appear to lie for direct material gain and expressed confusion about his behavior, further supporting a pathological rather than strategic interpretation.

Birch and colleagues (2006) described the case of Lorraine, whose extensive fabrications led to wrongful accusations, legal proceedings, and severe harm to others. Lorraine repeatedly reported elaborate death threats and assaults, implicating coworkers, friends, and family members. Her lies escalated over time, eventually including fabricated arson and false allegations against a young child. During a forensic assessment, she admitted to lying but reported that she did not know why she had done so.

A related but distinct category of cases involves individuals in positions of authority whose pathological lying leads to professional downfall. One such example is the case of Judge Patrick, reported by the Commission on Judicial Performance (2001). Judge Patrick systematically misrepresented his educational background, legal experience, and military service, including false claims of combat duty and receipt of a Purple Heart. Despite acknowledging that the information was false, he minimized his responsibility and attributed the misrepresentations to others. 

Across these diverse cases—spanning clinical, forensic, and professional contexts—several consistent features emerge. Pathological lies are often elaborate, persistent, and self-referential. They frequently portray the individual as exceptional, heroic, or victimized, and they tend to escalate over time as earlier lies require reinforcement. The behavior typically begins in adolescence or early adulthood and persists for years or decades. Importantly, many pathological liars recognize that they are lying, yet report limited control over the behavior and experience significant distress and impairment as a result.

Although individual presentations vary, the remarkable consistency of core features across historical periods and cultural contexts supports the argument that pathological lying cannot be fully explained as ordinary dishonesty, antisocial manipulation, or symptom substitution. These cases form the empirical foundation for contemporary theoretical models and diagnostic proposals.

References

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