Why are some people more manipulative, self-centred, callous or cruel than others? Personality psychology offers a framework for understanding these differences, and the answers are more complicated than they might initially appear.
Most human relationships depend upon a degree of trust, fairness and mutual restraint. We generally expect other people to respect our interests, behave with some consideration and refrain from exploiting us simply because an opportunity presents itself. Yet these expectations are not universally shared. Some individuals appear unusually willing to manipulate those around them, pursue admiration at the expense of others, disregard the consequences of their actions or even derive satisfaction from another person's distress. Although such behaviour is often discussed in moral terms, psychologists have also attempted to understand it through the systematic study of personality.
Human personality encompasses an enormous range of characteristics, from kindness, curiosity and conscientiousness to selfishness, manipulation and aggression. These tendencies are neither equally distributed nor necessarily confined to people who commit crimes or exhibit serious psychological disturbances. Most people occasionally behave selfishly, exaggerate their achievements, manipulate a situation to their advantage or experience satisfaction at the misfortune of someone they dislike. What distinguishes individuals is the extent to which such tendencies form relatively consistent patterns in their attitudes, motivations and behaviour. Someone who occasionally tells a self-serving lie is not necessarily a manipulative person, just as someone who enjoys recognition is not automatically narcissistic.
One influential approach to studying these differences is known as the Dark Triad of personality, a framework encompassing three related characteristics: Machiavellianism, narcissism and psychopathy. These traits share an association with socially antagonistic behaviour, although each emphasises a somewhat different approach to other people. Machiavellianism concerns calculated manipulation and the strategic pursuit of personal advantage; narcissism involves an exaggerated sense of personal importance and a desire for admiration; and psychopathy encompasses characteristics such as callousness, limited remorse and behavioural disinhibition. Researchers subsequently investigated everyday sadism, the tendency to derive enjoyment from another person's suffering or discomfort, as a fourth characteristic. Its inclusion produced the framework now commonly called the Dark Tetrad.
Despite their dramatic names, these constructs should not be understood as a simple division of humanity into good and bad people. Modern personality psychology generally treats such characteristics as dimensions along which individuals vary, rather than qualities that are either completely present or entirely absent. Someone may exhibit relatively strong narcissistic tendencies while showing little inclination towards cruelty, for example, or possess a calculating interpersonal style without being particularly impulsive or aggressive. The Dark Tetrad provides a way of examining these differences systematically, while also raising important questions about what the traits have in common, how reliably they can be measured and how much they can tell us about behaviour in everyday life.
The origins of the Dark Triad
Although the Dark Triad was formally introduced in 2002, its intellectual foundations extend considerably further back. The psychological study of Machiavellianism developed particularly through the work of Richard Christie and Florence Geis, whose 1970 book Studies in Machiavellianism examined manipulative attitudes and interpersonal behaviour. Their research included the development of the Mach-IV questionnaire, which sought to measure differences in cynical beliefs and attitudes towards manipulation. Narcissism had an even longer history in psychological theory, having been examined within psychoanalysis and subsequently investigated through personality and clinical research. Psychopathy also possessed an established research tradition, particularly in clinical and forensic psychology, where instruments such as Robert Hare's Psychopathy Checklist were developed to assess psychopathic characteristics. These different research traditions helped provide the conceptual background for later studies of dark personality in nonclinical populations, although their instruments and definitions were not interchangeable.
The Dark Triad itself was introduced by psychologists Delroy Paulhus and Kevin Williams in their 2002 paper The Dark Triad of Personality: Narcissism, Machiavellianism, and Psychopathy. Although all three characteristics had been studied previously, much of the earlier research had treated them as separate subjects. Paulhus and Williams were interested in their similarities, particularly their shared associations with self-interest, manipulation and interpersonal antagonism. Their central question was whether these apparently different constructs represented distinct aspects of personality or were largely alternative descriptions of the same underlying disposition.
The researchers examined measures of the three traits in a sample of university students, investigating how strongly the characteristics were associated with one another and with broader personality dimensions. They found that Machiavellianism, narcissism and psychopathy were positively correlated, meaning that people with elevated scores on one trait were somewhat more likely to have elevated scores on the others. Nevertheless, the correlations were not so strong as to make the three constructs interchangeable, and each displayed somewhat different relationships with other personality characteristics. Their findings supported the view that these were related but distinguishable traits, providing a basis for investigating them collectively without assuming that they were identical.
This was an important development because superficially similar behaviour can arise from quite different psychological motivations. Someone might deceive a colleague to secure a promotion, exaggerate their achievements to attract admiration or disregard the consequences of their actions because they feel relatively little guilt. Each behaviour can be socially harmful, but the underlying motivation differs. By examining Machiavellianism, narcissism and psychopathy separately, researchers hoped to develop a more precise understanding of the different ways in which personality can contribute to exploitation, conflict and antagonism.
Machiavellianism
Machiavellianism takes its name from Niccolò Machiavelli, the sixteenth-century Italian political thinker whose writings explored power, political strategy and the sometimes uncomfortable realities of human ambition. In contemporary personality psychology, Machiavellianism refers to a relatively calculating approach to interpersonal relationships, accompanied by cynical attitudes towards human nature and a willingness to manipulate others in pursuit of personal objectives. Individuals with elevated Machiavellian tendencies may regard trust, honesty and loyalty less as absolute principles than as considerations to be weighed against their own interests. They may be especially attentive to the motives and vulnerabilities of other people, recognising that social influence often depends upon understanding what others want and how they are likely to respond.
The defining characteristic of Machiavellianism is not simply strategic thinking, which can be both valuable and entirely legitimate, but the readiness to employ deception or exploitation when doing so appears advantageous. A person high in this trait might cultivate relationships primarily for their usefulness, conceal important information to maintain an advantage or adjust their outward behaviour according to what they believe others wish to see. Such behaviour need not involve open hostility or aggression; indeed, manipulation is frequently more effective when it appears cooperative, sympathetic or trustworthy. Nevertheless, it would be misleading to assume that every person with elevated Machiavellian traits is an accomplished strategist. Research has questioned whether people who endorse manipulative attitudes are necessarily more skilled at influencing others, making it important to distinguish the motivation to exploit from the actual ability to do so successfully.
Read the full guide to Machiavellianism for more on its characteristics, empathy and examples.
Narcissism
Narcissism is perhaps the most familiar of the dark personality traits, although its meaning in psychological research is considerably more specific than its increasingly casual use in everyday conversation. Within the original Dark Triad framework, narcissism primarily refers to grandiose narcissistic characteristics, including an inflated sense of personal importance, feelings of superiority, entitlement and a pronounced desire for admiration. Individuals with elevated levels of these tendencies may regard themselves as unusually talented, attractive or deserving of recognition, and may be strongly motivated to obtain positions that affirm their perceived significance. Their social relationships can become closely connected to the maintenance of a favourable self-image, particularly when recognition, admiration or status is at stake.
Narcissism should not, however, be confused with ordinary confidence, ambition or healthy self-esteem. A confident person may recognise their abilities without requiring constant reassurance of their superiority, whereas narcissistic grandiosity more frequently involves exaggerated self-evaluation, entitlement and an expectation of special treatment. A person might therefore possess considerable social confidence without being especially narcissistic, while someone else might be strongly preoccupied with status and recognition despite having relatively modest achievements. The underlying issue is not simply whether an individual thinks highly of themselves, but how their self-evaluation influences their attitudes towards other people and the importance they attach to receiving admiration.
An important complication is that grandiose narcissism is not the same as vulnerable narcissism. Whereas grandiose narcissism is associated with overt self-importance, assertiveness and self-promotion, vulnerable narcissism is more closely associated with insecurity, hypersensitivity to criticism, distrust and emotional distress. Both can involve entitlement and self-centredness, but their outward presentation and relationships with broader personality characteristics differ. Crucially, conventional Dark Triad questionnaires have generally emphasised grandiose narcissistic tendencies, meaning that they do not necessarily provide a comprehensive assessment of narcissism in all its forms. It would therefore be misleading to assume that every apparently confident narcissistic person is secretly insecure, just as it would be incorrect to conclude that someone displaying considerable insecurity must possess narcissistic traits.
Read the full guide to narcissism for more on its expressions, self-image, relationships and examples.
Psychopathy
Psychopathy carries particularly strong associations with violent crime, dangerousness and the dramatic portrayals of psychopaths in popular culture. These associations can obscure the broader meaning of the construct in personality research, where psychopathic tendencies are often studied as measurable differences within the general population. Depending on the theoretical model and assessment instrument, relevant characteristics can include callousness, limited remorse, reduced concern for others, impulsivity, irresponsibility and a willingness to violate social rules. Individuals with elevated levels of certain psychopathic traits may be less restrained by guilt, fear of consequences or consideration for the people affected by their actions, although the extent to which these characteristics occur together varies considerably.
One influential account, developed by Christopher Patrick and his colleagues, describes psychopathy through three broad dimensions: boldness, meanness and disinhibition. Boldness encompasses characteristics such as fearlessness, social confidence and emotional resilience, while meanness involves callousness, exploitation and limited concern for others. Disinhibition refers to difficulties with impulse control, behavioural restraint and the regulation of immediate reactions. This model illustrates why psychopathy cannot be reduced to a single characteristic such as emotional coldness or fearlessness. A person may be exceptionally confident and relatively unaffected by stressful situations without showing pronounced cruelty or antisocial behaviour, while another may exhibit substantial impulsivity without possessing the same degree of social boldness.
It is also important to recognise that different traditions within psychopathy research place different emphases on these characteristics. Clinical and forensic assessments are concerned with broader patterns of personality and behaviour, sometimes incorporating substantial evidence from interviews and personal histories, whereas general-population questionnaires typically focus on self-reported personality tendencies. Whether boldness should be considered a central feature of psychopathy, for example, has itself been debated. Consequently, a high score on a psychopathy-related personality scale should never be treated as equivalent to a clinical diagnosis or as evidence that an individual is inevitably dangerous, criminal or incapable of meaningful relationships.
Read the full guide to psychopathy for more on its dimensions, emotional responsiveness, examples and assessment limits.
Everyday sadism
The fourth member of the Dark Tetrad, everyday sadism, concerns the tendency to derive pleasure or satisfaction from another person's suffering, humiliation or discomfort. Although sadism has long been discussed in psychology, its investigation as a personality characteristic within the general population developed more recently. Researchers became interested in whether the original Dark Triad adequately captured the motivations underlying deliberately cruel behaviour, particularly in situations where causing harm offered little obvious material or social advantage. The central distinction is that sadism involves finding cruelty itself rewarding, rather than merely tolerating harm as an unfortunate consequence of pursuing another objective.
In a notable 2013 study, Erin Buckels, Daniel Jones and Delroy Paulhus investigated everyday sadism using experimental tasks designed to examine participants' willingness to engage in apparently harmful behaviour. Their research included a task involving the apparent killing of insects and another examining willingness to harm an innocent person within a controlled experimental setting. The results suggested that sadistic tendencies could predict certain forms of cruelty beyond the contributions of Machiavellianism, narcissism and psychopathy. Particularly striking was the finding that participants with higher sadistic tendencies were more willing to expend effort for an opportunity to cause harm. Such findings contributed to growing interest in treating everyday sadism as a fourth dark personality trait, although laboratory tasks necessarily provide a limited representation of the complicated circumstances in which cruelty occurs outside research settings.
The significance of everyday sadism lies in the distinction between instrumental and intrinsically rewarding harm. A highly Machiavellian individual might be willing to hurt someone because doing so provides an advantage, while a person high in sadistic tendencies may find the suffering itself satisfying. Everyday sadism does not necessarily involve extreme violence or criminal behaviour; it may also be expressed through deliberate humiliation, malicious provocation or deriving amusement from another person's discomfort. Nevertheless, isolated instances of enjoying competitive success, fictional violence or an opponent's embarrassment should not automatically be interpreted as evidence of an enduring sadistic disposition. As with the other dark traits, context, motivation and patterns of behaviour are essential to understanding what a particular action might signify.
Read the full guide to everyday sadism for more on its forms, distinctions, research and examples.
Similar behaviour, different motivations
The distinctions between the four characteristics become clearer when we consider how the same outward behaviour might arise from different motivations. Imagine an employee who deliberately takes credit for a colleague's work during an important presentation. If the behaviour is primarily Machiavellian, the employee may have calculated that claiming the achievement will improve their chances of promotion and decided that the personal advantage outweighs the risk of being discovered. If narcissistic tendencies are especially influential, the employee may be preoccupied with receiving admiration or convinced that their contribution deserves disproportionate recognition. Where psychopathy-related callousness or disinhibition is prominent, the employee may opportunistically claim the credit with relatively little concern about the colleague's distress or the consequences of being exposed. Someone motivated by everyday sadism, meanwhile, might find particular satisfaction in watching the colleague become embarrassed, powerless or upset.
These are simplified illustrations rather than four fixed categories of people. In reality, the same individual might be motivated by several considerations simultaneously, and outward behaviour alone rarely allows an observer to establish another person's psychological motives with confidence. A person who takes credit for someone else's work might be ambitious, insecure, dishonest, opportunistic or responding to pressures that are not immediately apparent. Nevertheless, the example demonstrates why researchers distinguish between different dark characteristics even when the behaviours associated with them sometimes overlap. The underlying psychological processes may matter as much as the observable actions.
These descriptions summarise characteristic themes in the research. They are not diagnostic criteria, and individuals can exhibit several tendencies at once.
What do the traits have in common?
Although the four traits emphasise different characteristics, their overlap is among the most important subjects in dark personality research. Machiavellianism, narcissism, psychopathy and sadism are all associated, to varying degrees, with interpersonal antagonism and a willingness to place personal interests above the welfare of others. These similarities help explain why scores on the different traits tend to be positively correlated. Someone who is relatively comfortable manipulating other people may also be more willing to disregard their feelings, while a person strongly motivated by superiority and status may respond antagonistically when their position is threatened. Nevertheless, the traits do not always occur together, and their differences can be informative when examining the motives behind particular behaviours.
This overlap has encouraged researchers to investigate whether the Dark Triad and Dark Tetrad reflect aspects of more general personality dimensions. Studies using the Big Five and HEXACO models have found important connections between dark traits and broader characteristics, particularly low Agreeableness and low Honesty–Humility. Agreeableness concerns tendencies such as cooperation, consideration and a willingness to maintain harmonious relationships, while Honesty–Humility encompasses sincerity, fairness, modesty and a reluctance to exploit others for personal gain. Individuals with lower levels of these characteristics are, on average, more likely to endorse certain attitudes and behaviours associated with the darker personality constructs. However, the strength of these relationships varies across traits and instruments, and broader personality dimensions do not necessarily capture every feature of the Dark Tetrad.
Some researchers have gone further by proposing a general underlying disposition known as the Dark Factor of Personality, or simply D. This approach, associated with research by Morten Moshagen and colleagues, suggests that a common tendency to prioritise one's own interests at the expense of others, accompanied by beliefs that justify such behaviour, may help explain the similarities between several socially aversive characteristics. From this perspective, Machiavellianism, narcissism, psychopathy and sadism can be understood partly as different expressions of a broader antagonistic disposition. The proposal does not necessarily mean that the individual traits are meaningless, but it raises the possibility that their shared psychological foundation may be more important than some of their apparent differences.
Indeed, one of the most significant criticisms of Dark Triad research concerns the extent to which certain constructs overlap in practice. Psychologists Joshua Miller, Donald Lynam and their colleagues have questioned whether commonly used self-report measures of Machiavellianism and psychopathy distinguish these characteristics as clearly as their separate names suggest. This relates to a broader problem in psychological measurement sometimes called the jangle fallacy, in which researchers use different names for constructs that may substantially overlap. Such criticism does not establish that manipulation, callousness and impulsivity are identical characteristics, but it does suggest that some questionnaires may not separate them effectively. The challenge for personality research is therefore to establish which aspects of dark personality are genuinely distinctive and which can be explained through broader dimensions such as antagonism or low Honesty–Humility.
Why might dark personality traits exist?
An intriguing question concerns why characteristics associated with exploitation and damaged relationships continue to appear throughout human populations. Cooperation has been enormously important to human social life, allowing individuals to share resources, form alliances, raise children and achieve objectives that would be difficult to accomplish independently. If trust and reciprocity are so advantageous, it is reasonable to wonder why tendencies towards manipulation, opportunism and disregard for others have not simply disappeared. Evolutionary psychologists have proposed several possible explanations, including the idea that certain antagonistic strategies may sometimes produce short-term advantages despite their longer-term social costs.
One hypothesis is that exploitative behaviour may offer advantages under particular conditions, especially when individuals can obtain benefits without facing repeated encounters with those they have harmed. Related ideas involve frequency-dependent selection, in which the potential success of a strategy depends partly on how common it is within a population. If most people behave cooperatively, a minority willing to exploit their trust may sometimes gain advantages, although widespread exploitation could undermine the cooperation on which such opportunities depend. Other researchers have examined connections between dark traits and life-history approaches involving differences in impulsivity, risk-taking, future orientation and reproductive behaviour.
These explanations remain hypotheses rather than settled accounts of why dark personality traits exist. Research has not consistently supported the idea that the entire Dark Triad reflects a single fast life-history strategy, and different components of narcissism and psychopathy may show quite different associations with the characteristics proposed by such theories. Moreover, demonstrating that a behaviour can sometimes provide an advantage does not establish that a particular psychological characteristic evolved specifically for that purpose. Environmental influences, learning, individual development and the many interacting components of personality must also be considered. Evolutionary perspectives can therefore provide interesting questions for investigation, but they should not be treated as definitive explanations of manipulation, narcissism or cruelty.
Why do these traits matter?
The Dark Tetrad offers researchers a framework for investigating aspects of personality that can have significant consequences for social relationships and everyday life. Much of human cooperation depends upon trust, reciprocity, empathy and the expectation that other people will exercise at least some restraint in pursuing their own interests. Characteristics such as manipulation, entitlement, callousness and enjoyment of cruelty can undermine these expectations, creating difficulties in personal relationships, workplaces and wider social environments. Researchers have consequently examined associations between dark personality traits and a range of outcomes, including interpersonal conflict, aggression, deception, exploitative behaviour and certain forms of workplace misconduct. Studying these relationships can help clarify why people differ in their willingness to exploit opportunities, disregard social obligations or inflict harm.
Researchers have also investigated demographic differences in dark personality characteristics. Some studies and meta-analyses have found that men, on average, obtain higher scores than women on certain dark personality measures, particularly those assessing psychopathy-related traits. Research on everyday sadism has also reported average differences in this direction, although findings and their magnitude depend upon the instruments and populations examined. Differences in narcissism and Machiavellianism are generally more modest or sensitive to measurement choices. Such findings describe statistical patterns across groups rather than fixed characteristics of men or women, and the distributions of scores overlap substantially. Group averages therefore provide little justification for making assumptions about the personality of a particular individual.
At the same time, it would be a mistake to treat elevated dark personality traits as a reliable prediction of how a particular person will behave. Personality characteristics are associated with tendencies and probabilities, not inevitable outcomes. Their expression depends upon circumstances, opportunities, incentives, social expectations and the many other characteristics that make up an individual's personality. Moreover, people are not always accurate judges of their own motives, and observed behaviour can have multiple explanations. An apparently cold decision may reflect calculated self-interest, emotional detachment, situational pressure or a combination of factors that cannot be determined from a personality label alone. Associations observed in research can therefore be useful for understanding patterns across populations without providing certainty about individual actions.
Can dark personality traits change?
An important question is whether dark personality characteristics remain relatively stable throughout life or change as individuals grow older. Longitudinal research suggests that personality is neither completely fixed nor endlessly changeable. A substantial 2024 meta-analysis by Ulrich Orth and colleagues, drawing upon 51 longitudinal samples involving more than 37,000 participants, found that several forms of narcissism tended to decline across the lifespan. However, individuals who were relatively narcissistic compared with their peers often maintained that relative position over time. This illustrates the distinction between changes in the average level of a trait and changes in the relative differences between individuals. A person can become less narcissistic with age while remaining more narcissistic than most other people of a similar age.
Research examining the development of the wider Dark Triad presents a more complicated picture. A large longitudinal study published in 2026 by Tadahiro Shimotsukasa and Atsushi Oshio examined changes in Machiavellianism, narcissism and psychopathy using seven waves of data from a Japanese population panel. The researchers found that the three traits did not follow identical developmental patterns, with differences emerging in both stability and average change across ages. In particular, narcissism and psychopathy showed more positive change at younger ages in this sample, while Machiavellianism displayed a different pattern. The authors emphasised that their findings were exploratory and subject to limitations, including the difficulty of separating age effects from generational and historical influences. Taken together, longitudinal studies suggest that dark personality characteristics can change over time, but that the direction and extent of change depend upon the particular trait, the population being studied and the methods used to measure it.
What are the limits of the framework?
The Dark Tetrad itself should also be regarded as a developing research framework rather than an unquestionable scientific classification. Although considerable evidence supports the usefulness of investigating these characteristics, researchers continue to examine the boundaries between them, the adequacy of existing assessment instruments and the extent to which their similarities can be explained by broader dimensions of personality. The overlap between Machiavellianism and psychopathy, the multidimensional nature of narcissism, the relationship between sadism and other antagonistic tendencies, and the limitations of self-report questionnaires remain important areas of scientific discussion. Such debates do not make the subject meaningless; rather, they reflect the difficulty of describing complex patterns of human motivation and behaviour using a manageable number of psychological constructs.
Conclusion
Ultimately, the value of the Dark Triad and Dark Tetrad lies in providing a more systematic understanding of characteristics that people often recognise in everyday life but struggle to describe precisely. The frameworks help distinguish calculated exploitation from the pursuit of admiration, callous indifference from impulsive behaviour, and instrumental aggression from the enjoyment of cruelty. They also remind us that personality is rarely a matter of simple categories. Individuals differ in the degree to which they exhibit particular tendencies, those tendencies overlap in complicated ways, and no single assessment can fully describe a person's character. Studying the darker side of personality is therefore not simply an exercise in identifying unpleasant people, but part of the broader scientific effort to understand the diversity of human motives, relationships and behaviour.
References
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Christie, R., & Geis, F. L. (1970). Studies in Machiavellianism. Academic Press.
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Paulhus, D. L., & Williams, K. M. (2002). The Dark Triad of personality: Narcissism, Machiavellianism, and psychopathy. Journal of Research in Personality, 36(6), 556–563. Read the paper
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Patrick, C. J., Fowles, D. C., & Krueger, R. F. (2009). Triarchic conceptualization of psychopathy: Developmental origins of disinhibition, boldness, and meanness. Development and Psychopathology, 21(3), 913–938. Read the paper
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McDonald, M. M., Donnellan, M. B., & Navarrete, C. D. (2012). A life history approach to understanding the Dark Triad. Personality and Individual Differences, 52(5), 601–605. Read the paper
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Buckels, E. E., Jones, D. N., & Paulhus, D. L. (2013). Behavioral confirmation of everyday sadism. Psychological Science, 24(11), 2201–2209. Read the paper
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Miller, J. D., Lynam, D. R., Hyatt, C. S., & Campbell, W. K. (2017). Controversies in narcissism. Annual Review of Clinical Psychology, 13, 291–315. Read the paper
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Moshagen, M., Hilbig, B. E., & Zettler, I. (2018). The dark core of personality. Psychological Review, 125(5), 656–688. Read the paper
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Miller, J. D., Vize, C., Crowe, M. L., & Lynam, D. R. (2019). A critical appraisal of the Dark Triad literature and suggestions for moving forward. Current Directions in Psychological Science, 28(4), 353–360. Read the paper
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Orth, U., Krauss, S., & Back, M. D. (2024). Development of narcissism across the life span: A meta-analytic review of longitudinal studies. Psychological Bulletin, 150(6), 643–665. Read the paper
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Shimotsukasa, T., & Oshio, A. (2026). Age-graded stability and change in Dark Triad traits: Seven-wave evidence from a large Japanese panel, with Big Five benchmarks. Journal of Personality. Advance online publication. Read the paper