From madness to genius: The Openness/Intellect trait domain as a paradoxical simplex

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Abstract

A novel theory of Openness/Intellect is proposed, which integrates intelligence and positive schizotypy (or apophenia, false detection of patterns or causal connections) within the Big Five. Openness/Intellect comprises a simplex of subtraits arrayed along a single scaling dimension. Openness traits fall in one half of the simplex, bounded by apophenia; Intellect traits fall in the other half, bounded by intelligence. The simplex is paradoxical because intelligence and apophenia are negatively correlated despite both loading positively on the general Openness/Intellect factor. The model was supported in two samples and organizes theories of (1) the relation of intelligence and schizotypy to personality, (2) the psychological and biological mechanisms involved in Openness/Intellect, and (3) the costs and benefits of Openness, proximally and evolutionarily.

Highlights

► A new model is proposed of the structure of the Openness/Intellect trait domain. ► Intelligence and positive schizotypy are integrated as facets of Openness/Intellect. ► Positive schizotypy is associated with Openness, intelligence with Intellect. ► A simplex model is supported in two samples using factor and scaling analysis. ► The model organizes theory and past research on the sources of Openness/Intellect.

Introduction

Genius has long been associated with madness in the popular as well as the artistic imagination. What do madness and genius have in common, and what separates them? We believe these questions may be related to two seemingly more mundane questions from personality psychology and psychometrics: What is the relation of intelligence to personality? and What is the relation of schizotypy to personality? The theory we present here addresses the latter two questions by suggesting that their solutions are linked and that the existence of each as a problem is due in part to the solution of the other. Our theory is designed to explain the nature of Openness/Intellect (one of the “Big Five” personality traits), which is the basic dimension of personality most related to many psychological phenomena that are quintessentially human, including art, imagination, creativity, and intellectual curiosity.

Central to the theory is a novel model of the structure of Openness/Intellect as a domain of personality traits, locating both intelligence and the positive symptoms of schizotypy as facets within this domain. This may at first seem unlikely. Surely, schizotypy and intelligence should be inversely related (the empirical evidence suggests as much), let alone conceived as part of the same broad trait dimension. Nonetheless, madness and genius may be similar in their association with unconventional perspectives on the world. Both the negative and the positive associations between schizotypy and intelligence are intuitively plausible, and this creates a puzzle. Even Poe, in our epigraph, vacillates between linking madness to the “loftiest intelligence” and suggesting that it comes at the expense of “general intellect”. Which is it? Can this paradox be resolved?

We propose that the full extent of the Openness/Intellect domain forms a paradoxical simplex, extending from intelligence at one end to apophenia at the other. Apophenia is the perception of patterns or causal connections where none exist. (We discuss below why this construct may be a desirable replacement for the construct of positive schizotypy in the context of personality theory.) Extreme apophenia might be seen as the epitome of madness. It is, at least, one important form of madness and the defining feature of psychosis. A simplex is an arrangement of variables along a single dimension, with those closest together most related and those farthest apart least related. (Note that this is not a trait dimension, which represents variability in a population, but a scaling dimension describing the magnitudes of relations among variables.) In this case, the simplex is paradoxical in that its opposite ends are hypothesized to be unrelated or even negatively related, despite the fact that all of its elements load positively on the same latent trait. This situation would imply that intelligence and apophenia may share some cause in common related to Openness/Intellect, though some other force drives them apart.

A key motive for developing this theory is desire for a structural model that can integrate the growing literature on the psychological and biological mechanisms that may be causes of traits in the Openness/Intellect domain (e.g., DeYoung et al., 2005, DeYoung et al., 2009, Jung et al., 2010, Kaufman et al., 2010, Peterson et al., 2002). The hierarchical organization of personality traits indicates that causes need to be considered at multiple breadths (DeYoung, 2010a). Some causal forces will influence Openness/Intellect as a whole, whereas others will be specific to lower-level traits within this domain. This principle has been demonstrated in behavior genetics, where lower-level traits in the Big Five hierarchy are found to be influenced by specific genetic factors that are independent of the genetic factors influencing the entirety of each Big Five domain (Jang et al., 1998, Jang et al., 2002). The Openness/Intellect domain appears likely to have a particularly complex array of causal sources because of the diversity of traits it encompasses, and its structure needs to be modeled in a manner reflecting this complexity.

The incentive for integrating intelligence and apophenia with the Big Five model stems from two premises. First, the Big Five can provide a reasonably comprehensive taxonomy for all broad categories of variability in psychological function in which there is substantial variation (e.g., reward sensitivity for Extraversion, cognitive exploration for Openness/Intellect; DeYoung, 2010b, Van Egeren, 2009). Given this premise, important traits such as intelligence and positive schizotypy must be integrated with the Big Five or else deemed to be unique to more specific categories of psychological function, unrelated to those represented by the Big Five. Second, personality traits should be explained mechanistically as variation in the functional parameters of the brain (DeYoung, 2010a). Because the brain is a single system of interacting elements, mechanistic theories for all specific traits should be compatible and ultimately unified. Both intelligence and apophenia are linked to Openness/Intellect not only through psychometrics but also through overlapping biological substrates (DeYoung et al., 2009, Jung et al., 2010). A unified, mechanistic theory of personality is therefore likely to require the conceptual integration of these two traits with Openness/Intellect. Note that the proposed integration does not require any radical reconceptualization of the Big Five (our model considers intelligence and apophenia to be relatively peripheral facets of the Openness/Intellect domain) but offers clarification of two important traits for which both conceptual and empirical difficulties have hitherto prevented integration with general models of personality.

In what follows, we first situate our theory in the relevant literature on Openness/Intellect, intelligence, and schizotypy. Next, we turn to data to test the model. Finally, we utilize our structural model to organize hypotheses regarding the likely mechanisms and processes, both proximal and evolutionary, involved in the traits encompassed by the Openness/Intellect domain and responsible for creating the paradoxical simplex structure of this domain.

Openness/Intellect is one of the Big Five personality traits identified through factor analysis of ratings of adjectives from the lexicon and scales from personality questionnaires (John et al., 2008, Markon et al., 2005)—with the other four being Extraversion, Neuroticism, Agreeableness, and Conscientiousness. The Big Five model captures most of the covariance among more specific personality traits. Although some argument exists as to whether a six factor model might be more appropriate in lexical research (Ashton et al., 2004, Saucier, 2009), the five and six factor models are very similar and both include Openness/Intellect as one broad domain including traits related to imagination, curiosity, creativity, intellectual interests, perceived intelligence, artistic and aesthetic interests, and unconventionality. Given the goal of a comprehensive taxonomy and the content of Openness/Intellect, it is reasonable to investigate whether intelligence and schizotypal traits can be incorporated within this domain.

As reflected in its compound label, the Openness/Intellect domain has been the most difficult of the Big Five for which to provide an adequate concise description. One early suggestion, Culture, has been deemed clearly inadequate, and the two most common labels currently are Openness to Experience and Intellect. The trend toward a compound label reflects the recognition that Openness and Intellect reflect two equally important aspects of the broader trait, which are separable despite being correlated (DeYoung et al., 2007, Johnson, 1994, Saucier, 1992, Saucier, 1994). In the hierarchical organization of personality, Openness and Intellect can be considered distinct traits below the Big Five, whereas the Big Five domain itself (Openness/Intellect) reflects the shared variance of these two lower-level traits. Saucier, 1992, Saucier, 1994 has proposed that “Imagination” might be a good single label for the domain as a whole, given the existence of both intellectual and aesthetic forms of imagination. However, we maintain the more common, compound label “Openness/Intellect,” when referring to the domain as a whole, because colloquially “imagination” has specific connotations that are too narrow to capture the full extent of this complex trait domain. Whenever we refer to “Openness” or “Intellect” alone, we are referring to a subtrait that constitutes one aspect of this domain.

The psychological function that appears to be common to all of the traits encompassed by the Openness/Intellect domain is cognitive exploration of the structure of both inner and outer experience, with cognition understood broadly to include both reasoning and perceptual processes (DeYoung, 2011, DeYoung et al., 2005, Van Egeren, 2009). Individuals high in Openness/Intellect display the ability and tendency to seek, detect, comprehend, and utilize more information than those low in Openness/Intellect. Intellect appears to reflect engagement primarily with abstract or semantic information, whereas Openness appears to reflect engagement primarily with perceptual or sensory information. Intellect is represented in lexical studies by adjectives like, “intellectual,” “intelligent,” “clever,” and “philosophical,” whereas Openness is represented by adjectives like, “artistic,” “perceptive,” “poetic,” and “fantasy-prone.” The lexicon also includes adjectives representative of both Intellect and Openness, such as “imaginative,” “original,” “curious,” and “innovative.”

Distinct descriptors of Openness and Intellect can be found not just in adjectives from the lexicon but also in personality questionnaires. A factor analysis of 15 lower-level facet scales in the Openness/Intellect domain found evidence for exactly two factors, which clearly represented Openness and Intellect (DeYoung et al., 2007). These two factors were characterized by correlating them with over 2500 items from the International Personality Item Pool (IPIP; Goldberg, 1999a). Intellect was related to intellectual engagement (e.g., “Avoid philosophical discussions” – reversed) and perceived intelligence (e.g., “Am quick to understand things”), whereas Openness was related primarily to aesthetics (e.g., “See beauty in things that others might not notice”) and fantasy (e.g., “Seldom daydream” – reversed).

The existence of Openness and Intellect as two distinct aspects of a broader trait offers an approach to understanding how apophenia and intelligence might belong to the same trait domain. Importantly, like all traits, the Big Five are probabilistic entities: a high score on Openness/Intellect indicates an increased likelihood of high scores on its various subtraits but is not deterministic. Thus, people scoring high in Intellect will, on average, score higher in Openness than people scoring low in Intellect. However, the correlation between Openness and Intellect is far from perfect, so some people will score high in Intellect but only moderate or low in Openness, and vice versa. Some narrower subtraits within Openness and Intellect could even be relatively unrelated to each other. Our model incorporates the hypothesis that apophenia is the facet of Openness that is least related to Intellect, whereas intelligence is the facet of Intellect that is least related to Openness.

Intelligence is typically measured by ability tests with objectively correct answers. Intelligence test scores correlate with Openness/Intellect at around r = .3 (Ackerman and Heggestad, 1997, DeYoung, 2011). However, intelligence tests are more strongly related to Intellect than to Openness, and when Intellect and Openness are used as simultaneous predictors (thereby examining their unique rather than shared variance), only Intellect is associated with general intelligence (DeYoung, 2011, DeYoung et al., in press). Given that the average intercorrelation among facets of Openness/Intellect is only about .3 (Costa & McCrae, 1992b), and that intelligence tests and questionnaires do not share method variance, these results suggest that intelligence has the potential to be considered at least a peripheral facet of Openness/Intellect, located specifically within the Intellect aspect of this domain. Some have argued that the association of Openness/Intellect with intelligence is merely due to its association with verbal (or “crystallized”) intelligence, resulting from greater learning due to intellectual curiosity (e.g., e.g., Ashton et al., 2000, Bates and Shieles, 2003). However, unlike Openness/Intellect, Intellect is associated equally strongly with verbal (“crystallized”) and nonverbal (“fluid”) intelligence (DeYoung et al., in press).

Considering intelligence as a facet of Intellect is consistent with evidence from factor analysis showing that lexical and questionnaire descriptors of intelligence fall within Openness/Intellect in the Big Five (DeYoung et al., 2007, Goldberg, 1990, Saucier, 1992). Nonetheless, considerable debate has taken place regarding whether intelligence, as measured by ability tests, is validly considered part of Openness/Intellect (e.g., Costa and McCrae, 1992a, McCrae and Costa, 1997; for more complete review of this debate see DeYoung, 2011). Clearly, self- or peer-ratings of intelligence should not be used as a proxy for tests of intelligence, given their correlation of about .3 with the latter (DeYoung, 2011; Paulhus, Lysy, & Yik, 1998), but this limitation indicates the presence of error in self-reports of intelligence, not that intelligence must be external to the Big Five conceptually. To argue the latter is to confuse method with construct; the goal of questionnaire research is typically to understand actual patterns of behavior, motivation, emotion, and cognition, not just to understand how people answer questionnaires, and we should not categorically distinguish behavioral from questionnaire measures of personality in our structural models.

Some have argued against including intelligence in personality on the grounds that personality traits should reflect typical behavior rather than maximal ability (Cronbach, 1949). However, the lexical studies that led to the Big Five model have almost always included descriptors of abilities as well as typical behavior, and personality is a broad enough concept to cover both. Nor is Openness/Intellect the only domain that might include abilities; for example, empathy (within Agreeableness) and self-control (within Conscientiousness) can both be measured with ability tests (DeYoung, 2011, Mischel et al., 1989, Nettle and Liddle, 2008).

The major piece of empirical evidence used to argue against the inclusion of intelligence in the Big Five is that, if multiple intelligence tests are factor analyzed with personality questionnaires, they typically form a sixth factor, rather than loading on a factor with questionnaire variables reflecting Openness/Intellect (McCrae & Costa, 1997). Two artifacts may account for this finding, however (DeYoung, 2011). First, questionnaires and ability tests have different sources of method variance. All of the questionnaires share method variance that they do not share with any ability test, and vice versa. Shared method variance inflates intercorrelations among measures of the same type, relative to their correlations with the other type, and inclines the two types of measure to form separate factors, regardless of what they share substantively. The second possible artifact resembles what Cattell (1978) called a “bloated specific factor.” If multiple measures of a single lower-level trait are present among the variables to be factor analyzed, their intercorrelations may be strong enough to cause them to form a separate factor, even when the other factors recovered are at a higher level of the trait hierarchy and one of them should subsume the lower-level trait in question. Intelligence is often considered a broad trait, but, in a hierarchy based on the Big Five, intelligence would make up just a facet of Openness/Intellect (though it might nonetheless be subdivided into more specific traits, like verbal ability and perceptual reasoning, at a still lower level of the trait hierarchy). Integrating intelligence into the Big Five thus remains a viable possibility and one we believe may be achieved by a theory that captures the structural complexity of the Openness/Intellect domain.

Schizotypy is a construct that has been conceived both as liability for schizophrenia-spectrum disorders and as a trait reflecting subclinical levels of symptoms of schizophrenia-spectrum disorders in the general population. We emphasize the latter conception, although the two are not incompatible, as disorder may be likely with a sufficiently high level of the trait. Additionally, however, we would argue that the construct of schizotypy may not be ideal in research on normal personality variation because of its heterogeneity and because it implies dysfunction. Our primary interest is in characterizing the Openness/Intellect trait domain in normal personality, rather than informing research on schizophrenia-spectrum disorders.

Schizotypy is a complex construct, composed of multiple subfactors that probably stem from different sources. Factor analyses have suggested potential subfactors including positive schizotypy, negative schizotypy, cognitive disorganization, paranoia, asocial schizotypy, and nonconformity (Kwapil et al., 2008, van Kampen, 2006, Vollema et al., 1995). The best validated of these subfactors are positive and negative schizotypy. Positive schizotypy comprises magical ideation, perceptual aberration, and overinclusive thinking. Negative schizotypy primarily reflects anhedonia, lack of pleasure in both social and sensory experience. Previous research shows that positive schizotypy is positively related to Openness/Intellect, whereas negative schizotypy is negatively related to Openness/Intellect (Kwapil et al., 2008, Ross et al., 2002).

In our theory, we replace the label “positive schizotypy” with “apophenia,” a term coined by the German neurologist Klaus Conrad in 1958 (Brugger, 2001). Apophenia is the tendency to perceive meaningful patterns and causal connections where none in fact exist. This terminological substitution has two advantages for our purposes. First, apophenia is a much more common phenomenon than may be implied by relying on the constuct of schizotypy. In essence, apophenia simply reflects the general human propensity to Type I error—identifying a pattern as meaningful when in fact the observation is attributable to chance. Seeing faces in random visual patterns, mistaking random sounds for the calling of one’s name, committing the gambler’s fallacy (expecting that alternation is more likely than repetition in a random sequence), and believing that something may bring good or bad luck are common examples of mild apophenia. Apophenia is a useful construct because it highlights the fact that these mundane cognitions have something fundamental in common with more dramatic cognitive processes like magical ideation (e.g., belief in telepathy). Second, “apophenia” is a word specifically descriptive of the phenomenon in question, whereas the term “positive schizotypy” inherently contrasts the relevant trait with “negative schizotypy.” This contrast implies a coherence to schizotypy that may be illusory and also necessitates reference to the more complex construct of schizotypy, even when only apophenia is of interest.

The complexity of schizotypy may explain why it has been difficult to reach consensus about its relation to the Big Five. A significant push to describe the symptoms of personality disorders (PDs) in dimensional terms has resulted in much consensus regarding the ability to map PD symptoms onto four of the Big Five (Markon et al., 2005, O’Connor, 2005, Watson et al., 2008, Widiger and Mullins-Sweatt, 2009). However, Openness/Intellect is the one Big Five trait not involved in this consensus, and diagnoses of Schizotypal PD tend to be associated primarily with high Neuroticism and low Extraversion, rather than high Openness/Intellect (O’Connor, 2005, Samuel and Widiger, 2008). This may result from the fact that positive schizotypal symptoms, those involving apophenia, are not well represented in standard PD assessment, which entails that diagnoses of schizotypal PD often reflect primarily negative schizotypy (Tackett, Silberschmidt, Krueger, & Sponheim, 2008).

Attempts have been made to conceptualize and measure “Oddity” (Watson et al., 2008), “Peculiarity” (Tackett et al., 2008), or “Experiential Permeability” (Piedmont, Sherman, Sherman, Dy-Liacco, & Williams, 2009) as a fifth domain of PD symptoms related to positive schizotypy. In these studies, this fifth domain was always marked by scales measuring magical ideation, unusual perceptual experiences, and other forms of apophenia, which have been shown to be associated with Openness/Intellect in other studies (Kwapil et al., 2008, Miller and Tal, 2007, Ross et al., 2002). A recent effort to demonstrate the link between schizotypy and the Big Five more directly involved creating schizotypy scales derived specifically from individual facets of the Revised NEO Personality Inventory (NEO PI-R; Costa and McCrae, 1992a, Costa and McCrae, 1992b); this project utilized three facets from Openness to derive positive schizotypy scales labeled “Aberrant Perceptions,” “Aberrant Ideas,” and “Odd and Eccentric” (Edmundson, Lynam, Miller, Gore, & Widiger, 2011).

However, the studies just mentioned have come to very different conclusions about whether PD symptoms involving apophenia are subsumed within Openness/Intellect (Edmundson et al., 2011, Piedmont et al., 2009) or whether they are distinct from Openness/Intellect (Watson et al., 2008). Because our theoretical position is that apophenia should be subsumed within Openness/Intellect, it is worth considering the research of Watson et al. (2008) in more detail. We note first that when Watson et al. (2008) extracted five factors from their Study 1 data, Openness/Intellect and oddity scales jointly formed a single factor, which is consistent with our model. However, when they extracted six factors, the oddity scales and the Openness/Intellect scales formed separate factors. The latter finding may reflect the fact that this study did not distinguish clearly between Openness and Intellect. We suspect that with a sufficient number of separate markers for Openness and Intellect, a six-factor solution would be more likely to produce distinct Openness and Intellect factors (with measures of apophenia loading on Openness) than distinct oddity and Openness/Intellect factors. We were able to test this hypothesis in one sample.

Interestingly, in their third study, Watson et al. (2008) did derive separate Openness and Intellect factors, and found that an oddity factor was not related to either. This result is particularly important for the current research because it was found in one of the two samples on which we report below (the Eugene–Springfield community sample; ESCS; Goldberg, 1999a). Three facts convinced us that this finding should not discourage us from testing our hypotheses in the ESCS.

First, Watson et al. (2008) used a restricted set of Openness/Intellect markers, particularly for Openness, which they labeled “Culture” and for which they included only three facets, all describing aesthetic interests. They excluded facets related to fantasy-proneness, which clearly mark Openness (Costa and McCrae, 1992a, DeYoung et al., 2007), and which we would expect to be related to apophenia.

Second, Watson et al. (2008) included constructs other than apophenia within oddity. We do not claim that apophenia is the only way to be odd, but we do suspect that, of the various ways one can be odd, only apophenia is primarily related to Openness. In their factor analysis, Watson et al. (2008) utilized total scores for inventories that contain distinct subscales, rather than utilizing each subscale separately. This approach juxtaposes constructs that clearly reflect apophenia (e.g., magical ideation) with others that do not (e.g., dissociative amnesia)—and the latter may be primarily associated with Big Five domains other than Openness/Intellect. They also included a scale measuring obsessive–compulsive symptoms, which seems inadvisable, given that obsessive–compulsive symptoms are associated with Conscientiousness in the consensus dimensional model of PD symptoms (Markon et al., 2005, O’Connor, 2005, Widiger and Mullins-Sweatt, 2009). Because our hypothesis was simply that Openness is associated with apophenia, we did not form hypotheses regarding the association of Openness with dissociation, negative schizotypy, or any other subfactor of oddity or schizotypy, and we included only measures of apophenia in our analyses.

Third, Watson et al. (2008) performed their factor analysis on ESCS measures of Openness/Intellect and oddity in isolation. A better strategy would have been to include facets from all of the Big Five domains, in case some of the oddity scales had primary or strong secondary loadings on domains other than Openness/Intellect. Failure to do so, in conjunction with failure to separate measures of apophenia from other types of oddity, renders it impossible to conclude from their study that measures of apophenia do not have important loadings on an Openness factor.

In two existing samples, we tested the hypotheses (1) that measures of Openness, Intellect, intelligence, and apophenia would load positively on the same factor, in analysis of many Big Five facets (though because measures of intelligence and apophenia are expected to be at least weakly negatively correlated, their loadings should be suppressed and thus relatively low), and (2) that multidimensional scaling analysis would show that traits within this factor form a simplex, with intelligence at one end, adjacent to other measures of Intellect, and apophenia at the other, adjacent to other measures of Openness.

In our factor analyses, one might assume that a confirmatory approach would be desirable, given clear hypotheses about structure and the possibility of method artifacts related to intelligence tests. However, two considerations led us to the conclusion that exploratory factor analysis should be used in this case. First, when carrying out factor analysis on a highly diverse set of facet-levels traits, confirmatory analysis typically fails because of the fact that personality lacks simple structure (Costa and McCrae, 1992b, Hofstee et al., 1992). The number of cross-loadings necessary (from each latent Big Five trait to facets with a primary loading on a different Big Five trait) renders their a priori specification practically impossible. Well-fitting confirmatory models are therefore generally not possible in this context. Second, the method variance associated with intelligence tests cannot readily be separated from substantive variance by modeling a latent method factor. This difficulty is due to the fact that the shared variance of all such tests represents g, the general intelligence factor, as well as method variance. Shared substantive variance and shared method variance would thus be confounded if we included multiple intelligence tests in our factor analyses. Our strategy for avoiding the artifacts that may cause intelligence tests to form a separate factor was simply to include only one intelligence score in exploratory factor analyses, treating intelligence as a single facet-level trait.

Section snippets

Participants

This study used a sample of 175 participants (119 female, 56 male), described by DeYoung et al. (2005), who completed assessments of intelligence as well as personality, in a single laboratory session. All were university students in Toronto, Canada, ranging in age from 18 to 38 years (M = 21.2, SD = 2.9). Ethnically, the sample was 59% White, 19% East Asian, 9% Black, and less than 5% each for South Asian, Hispanic, or other. Although DeYoung et al. (2005) analyzed associations between the Big Five

Study 2

We turned to the ESCS to provide a more extensive sampling of the domain of traits in question. The remarkable breadth of assessments available in the ESCS enabled us to include Big Five measures of Openness/Intellect that better represented the Intellect aspect of this domain, as well as several other measures that were not originally designed to assess the Big Five. In addition to various measures of apophenia and a measure of intelligence, these included measures of Need for Cognition and

General discussion

In two studies, we demonstrated that the Openness/Intellect domain can be well described as a simplex, an arrangement of variables along a single dimension according to distances reflective of how strongly the variables are related to each other. The opposing ends of the simplex were occupied by intelligence and apophenia. The fact that this pattern replicated using different measures of intelligence and apophenia suggests it is likely to be robust, not simply due to the idiosyncracies of

Conclusion: madness and genius

The Openness/Intellect domain can be described as a simplex ranging from intelligence to apophenia. This model allows both psychometric and theoretical integration of a surprisingly large number of phenomena into a coherent framework. (We hope our integrative endeavor will not be seen as an instance of apophenia.) Returning to our initial question regarding the relation of madness to genius, we can now suggest that madness (as apophenia) may indeed be both the antithesis and the complement to

References (128)

  • C.G. DeYoung et al.

    Sources of cognitive exploration: Genetic variation in the prefrontal dopamine system predicts Openness/Intellect

    Journal of Research in Personality

    (2011)
  • S.E. Harris et al.

    The functional COMT polymorphism, Val158Met, is associated with logical memory and the personality trait intellect/imagination in a cohort of healthy 79 year olds

    Neuroscience Letters

    (2005)
  • J. Hewitt et al.

    The factor structure of schizotypy in a normal population

    Personality and Individual Differences

    (1989)
  • K.L. Jang et al.

    Genetic and environmental influences on the covariance of facets defining the domains of the five-factor model of personality

    Personality and Individual Differences

    (2002)
  • S.B. Kaufman et al.

    Implicit learning as an ability

    Cognition

    (2010)
  • R.R. McCrae et al.

    Conceptions and correlates of openness to experience

  • A.M. McIntosh et al.

    White matter tractography in bipolar disorder and schizophrenia

    Biological Psychiatry

    (2008)
  • H. Merckelbach et al.

    The Creative Experiences Questionnaire (CEQ): A brief self-report measure of fantasy proneness

    Personality and Individual Differences

    (2001)
  • G.F. Miller et al.

    Schizotypy versus openness and intelligence as predictors of creativity

    Schizophrenia Research

    (2007)
  • C. Mohr et al.

    Psychometric schizotypy modulates levodopa effects on lateralized lexical decision performance

    Journal of Psychiatric Research

    (2005)
  • D. Nettle

    Schizotypy and mental health amongst poets, visual artists, and mathematicians

    Journal of Research in Personality

    (2006)
  • J.B. Peterson et al.

    Openness and extraversion are associated with reduced latent inhibition: Replication and commentary

    Personality and Individual Differences

    (2002)
  • P.L. Ackerman et al.

    Intelligence, personality, and interests: Evidence for overlapping traits

    Psychological Bulletin

    (1997)
  • T.M. Amabile

    Creativity in context

    (1996)
  • A.F.T. Arnsten et al.

    Neurochemical modulation of prefrontal cortical function

  • M.C. Ashton et al.

    A six-factor structure of personality descriptive adjectives: Solutions from psycholexical studies in seven languages

    Journal of Personality and Social Psychology

    (2004)
  • M.C. Ashton et al.

    Fluid intelligence, crystallized intelligence, and the Openness/Intellect factor

    Journal of Research in Personality

    (2000)
  • S. Blackmore et al.

    Seeing things: Visual recognition and belief in the paranormal

    European Journal of Parapsychology

    (1994)
  • J. Block

    Personality as an affect-processing system: Toward an integrative theory

    (2002)
  • E. Bowden et al.

    Aha! Insight experience correlates with solution activation in the right hemisphere

    Psychonomic Bulletin and Review

    (2003)
  • P. Brugger

    From haunted brain to haunted science. A cognitive neuroscience view of paranormal and pseudoscientific thought

  • P. Brugger et al.

    Right hemispatial inattention and magical ideation

    European Archives of Psychiatry and Clinical Neuroscience

    (1997)
  • P. Brugger et al.

    “Meaningful” patterns in visual noise: Effects of lateral stimulation and the observer’s belief in ESP

    Psychopathology

    (1993)
  • J.T. Cacioppo et al.

    The need for cognition

    Journal of Personality and Social Psychology

    (1982)
  • J.T. Cacioppo et al.

    Dispositional differences in cognitive motivation: The life and times of individuals varying in need for cognition

    Psychological Bulletin

    (1996)
  • J.T. Cacioppo et al.

    The efficient assessment of need for cognition

    Journal of Personality Assessment

    (1984)
  • D.J. Cai et al.

    REM, not incubation, improves creativity by priming associative networks

    Proceedings of the National Academy of Science

    (2009)
  • D. Carney et al.

    The secret lives of liberals and conservatives: Personality profiles, interaction styles, and the things they leave behind

    Political Psychology

    (2008)
  • S. Carson et al.

    Decreased latent inhibition is associated with increased creative achievement in high-functioning individuals

    Journal of Personality and Social Psychology

    (2003)
  • R.B. Cattell

    Scienific use of factor analysis in behavioral and life sciences

    (1978)
  • R.A. Charlton et al.

    White matter damage on diffusion tensor imaging correlates with age-related cognitive decline

    Neurology

    (2006)
  • M.C. Chiang et al.

    Genetics of brain fiber architecture and intellectual performance

    The Journal of Neuroscience

    (2009)
  • D.C. Cicero et al.

    The aberrant salience inventory: A new measure of psychosis proneness

    Psychological Assessment

    (2010)
  • S.R. Conn et al.

    The 16PF fifth edition technical manual

    (1994)
  • P.T. Costa et al.

    NEO PI-R professional manual

    (1992)
  • L.J. Cronbach

    Essentials of psychological testing

    (1949)
  • M. Csikszentmihalyi

    Implications of a systems perspective for the study of creativity

  • R.A. Depue et al.

    Neurobiology of the structure of personality: Dopamine, facilitation of incentive motivation, and extraversion

    Behavioral and Brain Sciences

    (1999)
  • C.G. DeYoung

    Higher-order factors of the Big Five in a multi-informant sample

    Journal of Personality and Social Psychology

    (2006)
  • C.G. DeYoung

    Personality neuroscience and the biology of traits

    Social and Personality Psychology Compass

    (2010)
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