Elsevier

Evolution and Human Behavior

Volume 35, Issue 5, September 2014, Pages 415-424
Evolution and Human Behavior

Original Article
Autistic-like and schizotypal traits in a life history perspective: diametrical associations with impulsivity, sensation seeking, and sociosexual behavior

https://doi.org/10.1016/j.evolhumbehav.2014.05.007Get rights and content

Abstract

According to recent theoretical models, autistic-like and schizotypal traits can be regarded as opposite sides of a single continuum of variation in personality and cognition, and may be diametrically associated with individual differences in life history strategies. In this view, schizotypy is a psychological phenotype oriented toward high mating effort and reduced parenting, consistent with a fast life history strategy, whereas autistic-like traits contribute to a slow strategy characterized by reduced mating effort and high parental investment. In this study, we tested the hypothesis that autistic-like and schizotypal traits would be diametrically associated with unrestricted sociosexuality, impulsivity, and sensation seeking (three key behavioral correlates of fast life history strategies in humans) in a sample of 152 young adults (18–38 years). The results were consistent with a diametrical autism–schizotypy axis of individual variation. In line with our hypotheses, autism–schizotypy scores were uniquely associated with individual differences in impulsivity, sensation seeking, and sociosexual behavior, even after controlling for variation in Big Five personality traits. However, we found no significant associations with sociosexual attitude in the present sample. Our findings provide additional support for a life history model of autistic-like and schizotypal traits and demonstrate the heuristic value of this approach in the study of personality and psychopathology.

Introduction

Initially described as milder manifestations of psychopathology (Meehl, 1962, Wing, 1988), autistic-like and schizotypal traits stand at the boundary between normal and disordered variation. Autistic-like traits – also known as the “broader autistic phenotype” – comprise reduced social/communicative skills, narrow interests and repetitive behaviors, and heightened attention to patterns and details; they are elevated in patients with autism spectrum disorders (ASDs) as well as in their relatives (Baron-Cohen, Wheelwright, Skinner, Martin, & Clubley, 2001). Mirroring the distinction between positive and negative symptoms in schizophrenia, schizotypal traits include both positive schizotypy – a tendency to experience unusual cognitive and perceptual phenomena, magical ideation, and reference/paranoid thoughts – and negative schizotypy – traits of social anxiety, social withdrawal, and constricted affect. Measures of schizotypy usually include a third dimension labeled disorganization that reflects odd or eccentric patterns of speech and behavior. Schizotypal traits are elevated in relatives of psychotic patients and constitute a risk factor for schizophrenia spectrum disorders (SSDs; Claridge, 1997, van Os et al., 2009). Both autistic-like and schizotypal features show moderate to substantial heritability, with estimates in the .50–.70 range (Ericson et al., 2011, Hoekstra et al., 2007, Ronald et al., 2011).

While autistic-like and schizotypal traits can be associated with pathological outcomes, they are also found outside the clinical spectra of ASDs and SSDs, and are increasingly recognized as important dimensions of normal personality variation. Indeed, accumulating empirical findings show that moderate amounts of autistic and schizotypal features may confer desirable and potentially adaptive traits such as creativity, enhanced perceptual and spatial skills, and even artistic and scientific talent (e.g., Baron-Cohen et al., 2009, Fletcher-Watson et al., 2012, Happé and Vital, 2009, Kyaga et al., 2011, Nettle and Clegg, 2006, Stevenson and Gernsbacher, 2013). Intriguingly, there is evidence that autistic-like and schizotypal traits may be understood as functionally opposite sides of a single overarching continuum, as postulated in the diametrical model developed by Crespi and Badcock (2008).

The relation between autism spectrum disorders (ASDs) and schizophrenia spectrum disorders (SSDs) has been debated for the better part of a century (see Crespi, 2011, Crespi and Badcock, 2008). At the descriptive level, the two clusters of disorders show a number of overlapping features, including social discomfort, reduced social skills, and impaired or dysfunctional mindreading. In addition, several genes and chromosome regions have been implicated in the etiology of both ASDs and SSDs (e.g., Carroll & Owen, 2009; see Crespi, Stead, & Elliot, 2010). The phenotypic overlap with autism is stronger for negative symptoms of schizophrenia such as blunted affect, poverty of speech, and anhedonia than for positive symptoms such as delusions, hallucinations, and thought disorganization.

According to the diametrical model of autism and psychosis (Crespi & Badcock, 2008; see Crespi et al., 2010, Dinsdale et al., 2013), the commonalities between ASDs and SSDs are mostly superficial; the apparent phenotypic similarities between autistic features and negative psychotic symptoms actually reflect the action of largely opposite causal factors. On this view, ASDs and SSDs represent opposite pathological extremes in the development of the human social brain. The autistic extreme of the autism-psychosis continuum is characterized by high levels of mechanistic cognition (visuospatial abilities, cause–effect inference) and low levels of mentalistic cognition (communication deficits, reduced empathy and social understanding). In contrast, psychosis is characterized by high mentalistic and low mechanistic abilities; in SSDs, hyper-mentalizing – expressed in traits such as paranoid ideation, exaggerated sensitivity to nonverbal cues, and over-responsiveness to gaze – is characteristically associated with poor visuospatial abilities and failures in logical reasoning (Crespi and Badcock, 2008, Zhai et al., 2011). For different reasons, both profiles may result in a pattern of reduced social skills, dysfunctional mindreading, and high levels of social anxiety. In addition, the negative features of premorbid schizophrenia are liable to be misdiagnosed as autistic disorders in younger patients who later go on to develop SSDs, thus contributing to inflate the apparent diagnostic overlap between the two spectra (Crespi, 2011).

Further support for a diametrical relation between ASDs and SSDs comes from the divergent patterns of brain and body development associated with the two spectra. While the autism spectrum is marked by early overgrowth (e.g., high birth weight and length, large brain volume, fast childhood growth), psychosis correlates with reduced growth, especially during prenatal and early postnatal development (Crespi & Badcock, 2008). Finally, when the same genes are implicated in both ASDs and SSDs, the relevant genetic and/or epigenetic effects often show opposite functional profiles in the two spectra. For example, different mutations of the same gene may determine up-regulation of a molecular pathway in ASDs and down-regulation in SSDs; in other cases, ASDs and SSDs are associated with opposite patterns of copy number variation (more versus fewer copies of a genetic region), opposite methylation patterns (hyper- versus hypo-methylation), and so forth (see Crespi and Badcock, 2008, Crespi et al., 2010, Gilman et al., 2012; see also Kalkman, 2012). In particular, Crespi and Badcock (2008) reviewed evidence that ASDs are associated with over-expression of paternally expressed imprinted genes (i.e., genes that are differentially expressed depending on a chromosome's parent of origin) and/or under-expression of maternally expressed genes, while SSDs tend to show the opposite expression pattern.

It is important to stress that, in this model, not all etiological factors are assumed to operate in a diametrical fashion. For example, deleterious mutations that affect neural integrity and developmental insults such as infections and nutritional deficits are likely to act as non-specific risk factors for both kinds of disorders (Crespi, 2011, Crespi et al., 2010; see also Keller & Miller, 2006).

The logic of the diametrical model is not restricted to diagnosable disorders, but extends to normative individual variation in autistic-like and schizotypal traits. According to the model, autistic-like traits and schizotypy represent opposite sides of a mechanistic–mentalistic continuum, with ASDs and SSDs as pathological extremes (Crespi and Badcock, 2008, Dinsdale et al., 2013). For example, Brosnan, Daggar, and Collomosse (2010) found that a profile of high empathizing and low systemizing specifically predicted the occurrence of positive symptoms in a female sample. Russell-Smith, Maybery, and Bayliss (2010) showed that autistic-like and positive schizotypal traits had diametrical associations with performance on a perceptual task involving local visual processing. In another study, Russell-Smith, Bayliss, Maybery, and Tomkinson (2013) tested the association between autistic-like and schizotypal traits and various measures of mechanistic and mentalistic cognition, with mostly null results. However, the analytic strategy employed by these authors (comparing matched groups of N = 20 extracted from a larger sample) suffers from low statistical power and a high likelihood of Type II errors.

In non-clinical samples, questionnaire measures of autistic-like and schizotypal traits show moderate positive correlations with one another. This pattern is explained by the large statistical overlap that exists between negative schizotypy and the interpersonal facet of autistic-like traits (Del Giudice et al., 2010, Dinsdale et al., 2013; see also Russell-Smith, Maybery, & Bayliss, 2011). However, such overlap is likely to be at least in part spurious, reflecting vague formulation of questionnaire items rather than true phenotypic similarity (discussed in Del Giudice et al., 2010).

When the overlap with negative schizotypy is statistically controlled for, measures of positive schizotypy and autistic-like traits become approximately orthogonal (reviewed in Del Giudice et al., 2010, Dinsdale et al., 2013), suggesting a two-dimensional structure rather than a single bipolar continuum.1 This, however, is only one possible interpretation of the data. In a recent study, Dinsdale et al. (2013) applied principal component analysis (PCA) to a mixture of scales assessing autistic-like and schizotypal traits. The first unrotated component captured the common variance attributable to general manifestations of social isolation, impairment, and/or anxiety (as well as shared method variance due to item similarity). After the first component was extracted, the second component showed a clear-cut diametrical structure, with opposite loadings from scales measuring positive schizotypy and autistic-like traits (Fig. 1c). As can be seen in Fig. 1c, negative schizotypy and disorganization have smaller loadings on the bipolar factor, thus falling in the middle of the autistic-schizotypal continuum. This finding was replicated in a previously published dataset by Wakabayashi, Baron-Cohen, and Ashwin (2012); see Dinsdale et al., 2013 and Fig. 1d.

In fact, questionnaire data are equally consistent with two mathematically equivalent psychometric structures: (a) a bipolar autism–schizotypy factor coupled with an orthogonal unipolar factor of social difficulty; and (b) two orthogonal unipolar factors of autistic-like traits (plus negative schizotypy) and positive schizotypy (plus disorganization). As shown in Fig. 1, the latter is readily obtained as an orthogonal rotation of the former. Whereas unrotated solutions tend to recover a general factor followed by a number of smaller bipolar factors, standard rotation algorithms (e.g., Varimax) are designed to break down general and bipolar factors to approximate a “simple structure”, whereby each of the variables tends to load highly on some of the factors and have small loadings on the other factors (see Darton, 1980, Russell, 2002). Although the simple structure criterion can be a useful exploratory heuristic, it becomes highly misleading when the variables do reflect a bipolar construct, such as the mentalistic–mechanistic continuum hypothesized in the diametrical model. When this is the case, the unrotated solution offers a more meaningful description of the data. The diametrical model offers a priori reasons to expect a bipolar continuum rather than two independent constructs, and is corroborated by genetic and developmental evidence of diametrical effects in the etiology of autism and psychosis (see above). For these reasons, it may be theoretically preferable to interpret the data as consistent with a bipolar dimension of autism versus positive schizotypy.

While Crespi and Badcock's model offers an elegant unified description of autistic and schizotypal traits, it does not provide a compelling evolutionary explanation for the maintenance of individual differences across generations, except as a result of intragenomic conflict between maternally and paternally derived genes (see Crespi & Badcock, 2008). Del Giudice et al. (2010) argued that, regardless of the initial reasons for the evolution of autistic and schizotypal features (including their potential survival benefits), sexual selection may contribute to maintain them in human populations because of their diametrical effects on mating- and parenting-related behaviors. In a nutshell, schizotypy is regarded as a psychological phenotype oriented toward high mating effort and reduced parenting, consistent with a fast life history strategy (see Kaplan and Gangestad, 2005, Stearns, 1992). On the contrary, autistic-like traits are hypothesized to contribute to slow life history strategy characterized by reduced mating effort coupled with high parental investment.

If the autism–schizotypy continuum is functionally linked to individual differences in life history strategy, various selective processes may be invoked to explain the maintenance of genetic variation in autistic-like and schizotypal traits. To begin, alternative strategies may be subject to negative frequency-dependent selection; for example, fast strategists that invest heavily in mating effort and early reproduction may be especially successful when most other individuals are engaging in slower, parenting-oriented strategies. Also, temporal and spatial variability in life history-relevant parameters such as mortality risk and resource availability (see Ellis, Figueredo, Brumbach, & Schlomer, 2009) can maintain genetic polymorphism in life history-related traits, especially in species with overlapping generations such as humans (Ellner & Hairston, 1994; see also Réale et al., 2010). In particular, temporal fluctuations in sex ratios have been proposed as a source of genetic variation in mating- and parenting-related traits in human populations (Del Giudice, 2012). While spatial and temporal variability may also favor the evolution of plastic organisms that respond facultatively to environmental cues, evolutionary models show that developmental plasticity can coexist with various amounts of genetic variation in the same traits (e.g., Draghi and Whitlock, 2012, Svanbäck et al., 2009).

The association between schizotypy and elevated mating effort has been discussed by various authors (Nettle, 2001, Nettle, 2006a, Shaner et al., 2004). According to the sexual selection model of schizotypy, schizotypy-increasing alleles affect brain processes so as to increase traits such as verbal and artistic creativity, thus conferring mating advantages on those individuals who do not develop a psychiatric condition. However, the outcomes of schizotypy may be either beneficial (greater mating success) or harmful (schizophrenia), depending in part on the individual's genetic quality (including lack of deleterious mutations) and developmental condition. Verbal/artistic creativity would then function as a sexually selected indicator of individual fitness (see Shaner et al., 2004), with schizotypy acting as an “amplifier” of individual differences in genetic quality and condition. The sexual selection model is thus consistent with a central role of mutation load in the etiology of SSDs, and is compatible with reduced fertility in schizophrenic patients and their close relatives (Del Giudice, 2010). Consistent with the sexual selection model, positive schizotypal traits are associated with verbal and artistic creativity, larger numbers of sexual partners, and unrestricted sociosexuality (Haselton and Miller, 2006, Kinney et al., 2001, Kyaga et al., 2011, Miller and Tal, 2007, Nettle, 2006b, Nettle and Clegg, 2006, Rawlings and Locarnini, 2008).

Del Giudice et al. (2010) extended the logic of the sexual selection model to the evolution of autistic-like traits. Specifically, they argued that autistic-like traits in the non-pathological range contribute to a slow life history phenotype geared toward high parental investment, low mating effort, and long-term allocation of resources. Mild autistic features can be expected to promote relational stability through a preference for routines and a predictable lifestyle, reduced novelty seeking and risk taking, and low interest in potential alternative partners. Moreover, the mechanistic abilities associated with autistic-like traits may significantly contribute to increased resource acquisition, perhaps especially so in agricultural and post-agricultural societies (discussed in Del Giudice et al., 2010). These features can be attractive in prospective long-term partners, especially from the standpoint of female choice—leading to stronger sexual selection for autistic-like traits in men. Clinically significant ASDs are seen as maladaptive syndromes resulting from excessive levels of trait expression, possibly combined with high mutation load and/or early developmental insults (Del Giudice, in press a). The idea that ASDs are functionally associated with slow life history strategies is also highly consistent with the recent proposal that the main cognitive and behavioral correlates of the autistic spectrum – both adaptive and maladaptive –can be framed in a heterochronic perspective as delays or non-completions of typical developmental trajectories (Crespi, 2013).

This hypothesis provides a novel explanation of the male-biased distribution of autistic-like traits and ASDs (Baron-Cohen et al., 2001), and is consistent with the (limited) evidence on the relational style associated with autistic features. People high in autistic-like traits report shorter duration of friendships but longer duration of romantic relationships (Jobe & White, 2007); moreover, their partners are on average just as satisfied as those of people low in autistic-like traits (Pollmann, Finkenauer, & Begeer, 2009). Intriguingly, interest in sexual and romantic relationships is usually conserved even in high-functioning ASDs, although the development of courtship and sexual abilities in these individuals follows a delayed trajectory (see Hellemans et al., 2007, Stokes et al., 2007). In a recent study, Bejerot and Eriksson (2014) found that high-functioning ASD patients of both sexes report lower sex drive, reduced orgasm frequency, and lower levels of stereotypically masculine traits such as assertiveness and competitiveness compared with same-sex controls.

The predictions of the diametrical sexual selection hypothesis were first tested in a sample of 199 Italian young adults (Del Giudice et al., 2010). Structural equation modeling (SEM) was employed to model the shared variance between autistic-like and negative schizotypal traits. In line with predictions, autistic-like traits predicted restricted sociosexuality, fewer sexual partners, stronger commitment to long-term relationships, and increased investment of time and resources in one's romantic partner. Positive schizotypy showed the opposite pattern of effects, while negative schizotypy displayed no significant association with mating-related measures once the overlap with autistic features was controlled for.

More recently, Del Giudice (in press a) integrated the sexual selection hypothesis into a broader life history framework for psychopathology. In this framework, ASDs are categorized as slow spectrum disorders because of their functional associations with indicators of slow life history strategies such as low mating effort, delayed sexuality, relationship stability, and low levels of impulsivity and sensation seeking (note that the model recognize the possibility of heterogeneity within ASDs, especially in the most severe forms). Other disorders in the slow spectrum include obsessive-compulsive personality disorder (OCPD), the reactive subtype of obsessive-compulsive disorder (OCD; see Lee & Kwon, 2003), and the perfectionistic and overcontrolled subtypes of eating disorders (see Westen & Harnden-Fischer, 2001). In contrast, SSDs are regarded as fast spectrum conditions (again with the possibility of some heterogeneity), together with disorders in the bipolar spectrum, externalizing disorders, borderline personality disorder (BPD), the autogenous subtype of OCD (Lee & Kwon, 2003), and the dysregulated subtype of eating disorders (Westen & Harnden-Fischer, 2001). All these conditions share a pattern of associations with fast life history indicators such as precocious sexuality, unrestricted sociosexuality, relationship instability, and high levels of impulsivity and sensation seeking.

Impulsivity and sensation seeking play a central role in the life history framework for psychopathology advanced by Del Giudice (in press a). Impulsivity is arguably the most important dimension of individual variation in self-regulation, and can be described as the tendency to act without deliberation and without consideration of future consequences—a combination of behavioral disinhibition and present orientation (DeYoung, 2011). In both humans and nonhuman animals, impulsivity is systematically associated with other behavioral indicators of fast life history strategy (reviewed in Del Giudice, in press aa, Del Giudice, in press bb). Indeed, virtually every behavioral trait associated with slow life histories – forming stable long-term relationships, refraining from short-term sexual opportunities, avoiding immediate risks, and so forth – is predicated on the ability to effectively inhibit present tendencies and prioritize long-term goals over short-term rewards.

Sensation seeking can be described as the tendency to seek out novel, stimulating, and emotionally intense experiences. Sensation seeking involves a tendency to take risks in the pursuit of thrills and excitement, is strongly correlated with impulsivity (DeYoung, 2011), and is an especially powerful predictor of investment in short-term mating (e.g., Lalasz & Weigel, 2011). Whereas men and women show similar average levels of impulsivity, sensation seeking is characteristically higher in men (Cross, Copping, & Campbell, 2011). Impulsivity and sensation seeking can be employed as behavioral “markers” of fast life history strategies, together with correlated traits such as attachment instability, sexual promiscuity, and social antagonism (see Del Giudice, in press a).

In the present study, we set out to replicate and extend some of the findings by Del Giudice et al. (2010) in a new sample from the United States. Specifically, we tested the hypothesis that autistic-like and schizotypal traits would show diametrical associations with measures of sociosexuality. In addition, we made the novel prediction that autistic-like and schizotypal traits would show diametrical associations with impulsivity and sensation seeking. Finally, we assessed the specificity of the predicted effects by controlling for correlations between autistic-like and schizotypal traits and “Big Five” personality factors (Costa & McCrae, 1995). We hypothesized that variation in autistic-like and schizotypal traits would predict individual differences in sociosexuality, impulsivity, and sensation seeking over and above the contribution of broad personality dimensions such as neuroticism, conscientiousness, and extraversion.

Section snippets

Participants and procedure

One hundred fifty-two men (N = 77) and women (N = 75) aged between 18 and 38 years (M = 22.7, SD = 3.8) took part in the study. Participants were 54.6% White, 17.8% Asian, 13.2% Black, and 14% of other/mixed ancestry; overall, 13.8% identified as Hispanic. Approximately 80% were undergraduate or graduate students at a private Midwestern university; most of the others were employed by the same university under various capacities (e.g., research or administrative staff). They were recruited through fliers

Data reduction

In preparation for the main analysis, we sought to reduce the data to a smaller number of summary variables so as to improve the robustness of the results. Means and standard deviations of the original variables are reported in Table 1. All analyses were performed in SPSS™ Statistics 20 (IBM Corporation, New York) and R™ 2.15 (R Core Team, 2012; packages psych 1.3.2 and reldist 1.6.2). To begin, we followed Dinsdale et al. (2013) and performed a principal component analysis (PCA) on the

Discussion

According to the diametrical model of autism and psychosis (Crespi & Badcock, 2008), autistic-like and schizotypal traits represent opposite sides of a mentalistic–mechanistic continuum of individual differences. A life history perspective puts the diametrical model in a broader context, suggesting that variation on the autistic-schizotypal axis may be maintained – at least in part – by the diametrical effects of autistic-like and schizotypal features on mating- and parenting-related behaviors (

Supplementary Materials

The following is the Supplementary data to this article.

Supplementary material

References (77)

  • D. Rawlings et al.

    Dimensional schizotypy, autism, and unusual word associations in artists and scientists

    Journal of Research in Personality

    (2008)
  • S.N. Russell-Smith et al.

    Relationships between autistic-like and schizotypy traits: An analysis using the Autism Spectrum Quotient and Oxford-Liverpool Inventory of Feelings and Experiences

    Personality and Individual Differences

    (2011)
  • A. Shaner et al.

    Schizophrenia as one extreme of a sexually selected fitness indicator

    Schizophrenia Research

    (2004)
  • A. Wakabayashi et al.

    Do the traits of autism-spectrum overlap with those of schizophrenia or obsessive-compulsive disorder in the general population?

    Research in Autism Spectrum Disorders

    (2012)
  • S.P. Whiteside et al.

    The Five Factor Model and impulsivity: Using a structural model of personality to understand impulsivity

    Personality and Individual Differences

    (2001)
  • J. Zhai et al.

    Risk variants in the S100B gene, associated with elevated S100B levels, are also associated with visuospatial disability of schizophrenia

    Behavioural Brain Research

    (2011)
  • A. Aleman et al.

    Sex differences in risk for schizophrenia: Evidence from meta-analysis

    Archives of General Psychiatry

    (2003)
  • J. Archer et al.

    Variability among males in sexually selected attributes

    Review of General Psychology

    (2003)
  • S. Baron-Cohen et al.

    Talent in autism: Hyper-systemizing, hyper-attention to detail and sensory hypersensitivity

    Philosophical Transactions of the Royal Society B

    (2009)
  • S. Baron-Cohen et al.

    The Autism-spectrum Quotient (AQ): Evidence from Asperger syndrome/high-functioning autism, males and females, scientists and mathematicians

    Journal of Autism and Developmental Disorders

    (2001)
  • S. Bejerot et al.

    Sexuality and gender role in autism spectrum disorder: A case control study

    PLoS ONE

    (2014)
  • M. Brosnan et al.

    The relationship between systemising and mental rotation and the implications for the extreme male brain theory of autism

    Journal of Autism and Developmental Disorders

    (2010)
  • L.S. Carroll et al.

    Genetic overlap between autism, schizophrenia and bipolar disorder

    Genome Medicine

    (2009)
  • G. Claridge

    Schizotypy: implications for illness and health

    (1997)
  • P.T.J. Costa et al.

    Domains and facets: Hierarchical personality assessment using the Revised NEO Personality Inventory

    Journal of Personality Assessment

    (1995)
  • B.J. Crespi

    One hundred years of insanity: Genomic, psychological, and evolutionary models of autism in relation to schizophrenia

  • B. Crespi

    Developmental heterochrony and the evolution of autistic perception, cognition and behavior

    BMC Medicine

    (2013)
  • B. Crespi et al.

    Psychosis and autism as diametrical disorders of the social brain

    Behavioral and Brain Sciences

    (2008)
  • B. Crespi et al.

    Comparative genomics of autism and schizophrenia

    Proceedings of the National Academy of Sciences of the United States of America

    (2010)
  • C.P. Cross et al.

    Sex differences in impulsivity: A meta-analysis

    Psychological Bulletin

    (2011)
  • R.A. Darton

    Rotation in factor analysis

    The Statistician

    (1980)
  • Del Giudice, M., Reduced fertility in patients’ families is consistent with the sexual selection model of schizophrenia...
  • Del Giudice, M. (in press a). An evolutionary life history framework for psychopathology. Psychological Inquiry....
  • Del Giudice, M. (in press b). Self-regulation in an evolutionary perspective. In G. H. E. Gendolla, S. Koole & M. Tops...
  • M. Del Giudice et al.

    The evolution of autistic-like and schizotypal traits: A sexual selection hypothesis

    Frontiers in Psychology

    (2010)
  • C.G. DeYoung

    Impulsivity as a personality trait

  • N.L. Dinsdale et al.

    How Are autism and schizotypy related? Evidence from a non-clinical population

    PLoS ONE

    (2013)
  • J.A. Draghi et al.

    Phenotypic plasticity facilitates mutational variance, genetic variance, and evolvability along the major axis of environmental variation

    Evolution

    (2012)
  • Cited by (0)

    View full text