Abstract
Recent discussions surrounding the Dark Triad (narcissism, psychopathy, and Machiavellianism) have centered on areas of distinctiveness and overlap. Given that interpersonal dysfunction is a core feature of Dark Triad traits, the current study uses self-report data from 562 undergraduate students to examine the interpersonal characteristics associated with narcissism, psychopathy, and Machiavellianism on four interpersonal circumplex (IPC) surfaces. The distinctiveness of these characteristics was examined using a novel bootstrapping methodology for computing confidence intervals around circumplex structural summary method parameters. Results suggest that Dark Triad traits exhibit distinct structural summary method parameters with narcissism characterized by high dominance, psychopathy characterized by a blend of high dominance and low affiliation, and Machiavellianism characterized by low affiliation on the problems, values, and efficacies IPC surfaces. Additionally, there was some heterogeneity in findings for different measures of psychopathy. Gender differences in structural summary parameters were examined, finding similar parameter values despite mean-level differences in Dark Triad traits. Finally, interpersonal information was integrated across different IPC surfaces to create profiles associated with each Dark Triad trait and to provide a more in-depth portrait of associated interpersonal dynamics.
The current study investigates the construct validity of the “Dark Triad” of personality traits (Paulhus & Williams, 2002). Specifically, we examine the interpersonal characteristics and distinctiveness of the Dark Triad using a multisurface interpersonal assessment approach (e.g., Dawood & Pincus, 2016) and a novel bootstrapping methodology for circumplex data (Zimmermann & Wright, 2017). The Dark Triad consists of three overlapping yet distinct and often socially aversive personality characteristics—narcissism, psychopathy, and Machiavellianism—each of which has extensive theoretical and research literatures within and independent of Dark Triad conceptualizations of these traits.
Narcissism can be defined as a person’s ability to maintain a positive view of the self through the use of regulatory strategies and self-enhancement experiences (Pincus et al., 2009). Although contemporary conceptualizations of narcissism include both narcissistic grandiosity and narcissistic vulnerability (Cain, Pincus, & Ansell, 2008; Pincus, Roche, & Good, 2015), narcissistic grandiosity is more closely associated with the Dark Triad construct (Furnham, Richards, & Paulhus, 2013; Miller & Campbell, 2008; Miller, Hoffman, et al., 2011). Narcissistic grandiosity can be characterized by both overt and covert expressions of arrogance, entitlement, superiority, and inflated self-image and is associated with aggression, disagreeableness, and dominance (Furnham et al., 2013; Miller, Hoffman, et al., 2011; Pincus, Cain, & Wright, 2014). Narcissistic grandiosity often results in maladaptive self-enhancement when individuals fail to transform their needs for recognition and admiration into socially appropriate ambitions and behaviors (Morf, Horvath, & Torchetti, 2011; Roche, Pincus, Lukowitsky, Ménard, & Conroy, 2013).
Psychopathy is a socially aversive personality pathology first operationalized by Hervey Cleckley (1941) using 16 criteria spanning not only antisocial behaviors but also emotional and interpersonal deficits and resilience to other psychopathologies (Cleckley, 1941). Since then, researchers have used these criteria to develop a number of psychopathy measures, including the Psychopathy Checklist–Revised (Hare, 1991), the Psychopathic Personality Inventory (Lilienfeld & Andrews, 1996), Levenson’s Self-Report Psychopathy Scale (Levenson, Kiehl, & Fitzpatrick, 1995), the Triarchic Personality Measure (Patrick, 2010), and the Self-Report Psychopathy Scale (SRP-III; Paulhus, Neumann, & Hare, in press). Researchers have also found ways to assess psychopathy using existing broad range personality measures like the Multidimensional Personality Questionnaire (MPQ; Tellegen, 1982). Although each of these can be used to assess psychopathy, correlations among measures typically range from .34 to .69 (Drislane, Patrick, & Arsal, 2014; K. M. Williams, Nathanson, & Paulhus, 2003), and factor analyses have suggested two- (Hare et al., 1990; Harpur, Hare, & Hakstian, 1989), three- (Patrick, Fowles, & Krueger, 2009), and four-factor (Hare & Neumann, 2005) solutions depending on the measure. Thus, a discussion of psychopathy depends, in part, on the measures used for its assessment. It is, therefore, important to understand the convergences and divergences of these measures and models.
For example, assessment of psychopathic traits using the MPQ results in a two-factor structure. The first factor, Fearless Dominance (FD), reflects emotional detachment and interpersonal difficulties and is characterized by low stress reaction and harm avoidance and high social potency (Benning, Patrick, Blonigen, Hicks, & Iacono, 2005; Benning, Patrick, Hicks, Blonigen, & Krueger, 2003; Verona, Patrick, & Joiner, 2001). Factor 2, Impulsive Antisociality (IA), reflects antisocial deviance and impulsivity. IA is characterized by high aggression, stress reaction, and alienation and low control (Benning et al., 2003; Harpur et al., 1989; Patrick, 1994; Verona et al., 2001). These factors tend to be weakly correlated/orthogonal with one another and show divergent and often opposite correlations with a number of criterion variables (Benning et al., 2003), causing some researchers to question whether FD should be part of the psychopathy construct (Miller & Lynam, 2012). Of these two factors, IA is conceptualized as being more closely associated with the construct as conceived of in the Dark Triad (Furnham et al., 2013). In contrast, assessment of psychopathic traits using the SRP-III results in a four-factor structure: Interpersonal Manipulation, Callous Affect, Erratic Lifestyle, and Criminal Tendencies (Neal & Sellbom, 2012). Correlations among factors range from .58 (Erratic Lifestyle and Criminal Tendencies) to .80 (Callous Affect and Interpersonal Manipulation; Neal & Sellbom, 2012). The total score on the SRP-III has demonstrated expected associations with a number of criterion measures. SRP-III total score has been positively associated with criminal and violent behavior, thrill seeking, irresponsibility, impulsivity, and callous affect and negatively associated with dependability, empathy, control, and honesty (Neal & Sellbom, 2012). Notably, the SRP-III total score is only correlated .34 with a composite of FD and IA (K. M. Williams et al., 2003), suggesting that these measures of psychopathy are related but not redundant with one another.
The construct of Machiavellianism is associated with diminished or absent affect in interpersonal relationships, amorality, psychological health, and little commitment to an ideology (Christie & Geis, 1970). Together, these characteristics describe an individual who is cynical, proficient at interpersonal manipulation, and lacks morality. More recent conceptualizations also include reputation building, planning, and coalition formation. For individuals high in Machiavellianism, impulse control, flexibility, adaptation to current circumstances, long-term goals, planning, and preparation are important strategies for success (Furnham et al., 2013; Jones & Paulhus, 2011).
Although each of these traits has a well-established literature in its own right, the expanding scope of each trait has resulted in empirical overlap, causing some researchers to conclude that these traits are measuring the same core construct and spurring the creation of composite indices of the Dark Triad that capture an exploitative social style that focuses on short-term goal attainment (Baughman, Dearing, Giammarco, & Vernon, 2012; Jonason, Li, & Teicher, 2010; Jonason, Li, Webster, & Schmitt, 2009; Jonason & Webster, 2010; McHoskey, Worzel, & Szyarto, 1998; Stead, Fekken, Kay, & McDermott, 2012). These researchers argue that Dark Triad traits share a high degree of aggression, self-aggrandizement, and deception, load onto a single latent factor, and often correlate more strongly with the Dark Triad composite than with individual Dark Triad traits.
Not all researchers agree with the use of composite measures of the Dark Triad. Glenn and Sellbom (2014) note a number of concerns with the use of these composites, including the assumption that Machiavellianism, psychopathy, and narcissism equally contribute to the composite. They suggest that grandiose narcissism and Machiavellianism can be subsumed into most definitions of psychopathy, citing a study by Jones and Figueredo (2013) that identified callousness and manipulation, both features of psychopathy, as necessary conditions for the development of a dark personality. Although they acknowledge the importance of comparing Dark Triad traits with one another, Glenn and Sellbom (2014) suggest that a Dark Triad composite measure is essentially a psychopathy measure that overemphasizes both grandiose narcissism and Machiavellianism without a strong theoretical rationale for doing so.
Additionally, there is a large body of research (Jones & Paulhus, 2011; Lee & Ashton, 2005; Paulhus & Williams, 2002; Rauthmann, 2012) suggesting that Dark Triad traits exhibit only moderate, positive, intercorrelations. A recent review reported that across a number of studies, the magnitude of the correlations is less than .50 in 75% of cases, with narcissism and Machiavellianism consistently exhibiting the smallest intercorrelations (Furnham et al., 2013). Dark Triad traits also exhibit differential relationships with certain antisocial behaviors. In particular, psychopathy is uniquely predictive of future delinquent behavior (K. M. Williams & Paulhus, 2004). Individuals high in psychopathy (but not narcissism or Machiavellianism) are more likely to respond aggressively to physical threats, have interactions with the legal system, bully others in adulthood, copy answers on exams, and enact fantasies of revenge (Baughman et al., 2012; DeLongis, Nathanson, & Paulhus, 2011; Jones & Paulhus, 2010; Nathanson, Paulhus, & Williams, 2006; K. M. Williams, McAndrew, Learn, Harms, & Paulhus, 2001). In contrast, individuals high in narcissism are more likely to demonstrate aggression in situations where their ego is threatened (Jones & Paulhus, 2010), while those high in Machiavellianism are more likely to bully others during adolescence and plagiarize essays (Nathanson et al., 2006; Peeters, Cillessen, & Scholte, 2010; Stickle, Kirkpatrick, & Brush, 2009).
Gender comparisons typically result in mean-level differences between men and women, where men score significantly higher on all three Dark Triad traits (Jonason et al., 2009; Paulhus & Williams, 2002). Despite these mean-level differences, correlations between Dark Triad traits and criterion variables, including Big Five personality traits, measures of cognitive ability and self-enhancement, and mate retention and poaching tactics, tend to be very similar, suggesting that although men have higher levels of Dark Triad traits, these traits seem to be functioning in similar ways across genders (Jonason et al., 2009; Jonason, Li, & Buss, 2010; Paulhus & Williams, 2002).
Given the current state of Dark Triad assessment and research, more clearly identifying points of similarity and difference among the Dark Triad traits is needed. Results that can identify distinct interpersonal characteristics of each trait would increase understanding of these personality dimensions and provide evidence for the construct validity of multitrait Dark Triad measures.
The Interpersonal Paradigm and the Interpersonal Circumplex
The interpersonal paradigm of personality assessment (Wiggins, 2003) provides an explicit and conceptually driven framework for integrating information from a number of disparate fields and serves as a nomological network, organizing and integrating both interpersonal variables and novel constructs. This framework clarifies the meaning of those constructs by locating them within the two-dimensional space defined by the Interpersonal Circumplex (IPC; Wiggins & Broughton, 1985; Figure 1). The IPC serves as the foundation for construct validation research using interpersonal theory and capitalizes on its geometric properties to quantitatively define an interpersonal surface (Wiggins & Broughton, 1991). The IPC is based on the assumption that two basic themes underlie social relationships: Dominance/Agency, related to autonomy and superiority, and Affiliation/Communion, related to helping and forming relationships with others (Bakan, 1966). When affiliation and dominance are placed on the x- and y-axes, respectively, in two-dimensional space and the various combinations of interpersonal tendencies are plotted, a circular pattern, or circumplex, emerges (Wiggins, 1979). This is true for a variety of circumplex surfaces representing different interpersonal constructs, including interpersonal problems (Alden, Wiggins, & Pincus, 1990; Soldz, Budman, Demby, & Merry, 1995), sensitivities (Hopwood, Ansell, et al., 2011), values (Locke, 2000), and efficacies (Locke & Sadler, 2007), which each have distinct interpersonal implications. The problems surface focuses on behaviors that the individual has difficulty enacting or that cause problems for the individual when enacted, while the sensitivities surface highlights behaviors that the individual finds bothersome when enacted by others. The values and efficacies surfaces focus on the importance that an individual engage in certain behaviors or have certain interpersonal experiences and the ability of the individual to effectively enact certain behaviors, respectively. In each case, these measures subdivide the IPC into 8 octants, each representing distinct interpersonal themes reflecting blends of dominance and affiliation.
The interpersonal circumplex.
Circumplex structure dictates that the relationship between octants is inversely proportional to the angular distance between the octants. Thus, scales that are adjacent to one another have content that is conceptually close and are strongly positively correlated. Scales that are orthogonal to one another are conceptually unrelated and correlated near zero, and scales that are diametrically opposed to one another are conceptual opposites and are strongly negatively correlated. 1 If an external criterion has distinct interpersonal content, the correlations between scores on the criterion measure and each octant score will form a cosine curve when plotted (Gurtman, 1994). The Structural Summary Method for circumplex data (SSM; Gurtman, 1992, 1994; Gurtman & Pincus, 2003) uses the characteristics of the cosine curve to quantitatively evaluate an external criterion within the nomological network of the IPC, reducing impressionistic interpretations of the data. The SSM summarizes the profile of eight correlations between IPC octants and an external criterion into four parameters: amplitude, elevation, angular displacement, and R2 (Figure 2).
Structural summary parameters (Wu, Roche, Dowgwillo, Wang, and Pincus, 2015).
Amplitude (a) refers to how differentiated the profile is, that is, to what extent the external construct exhibits distinctive interpersonal content. Elevation (e) refers to the association between the criterion variable and the general factor of the IPC measure. Angular displacement (Θ) refers to the location on the IPC associated with the dominant interpersonal theme of the external construct. Finally, R2 indicates the degree to which a perfect cosine curves fits the profile of correlations between an external criterion and the octant scores and, therefore, represents the prototypicality (vs. complexity) of the circular profile. An R2 value of .80 indicates good fit to a cosine curve, while an R2 value of .70 indicates acceptable fit (Zimmermann & Wright, 2017). Amplitude and angular displacement values are interpretable only when R2 is acceptably high. The elevation parameter does not depend on profile prototypicality. Although clear guidelines for interpreting elevation and amplitude are lacking, heuristic cutoffs of ≥|.15| have been proposed by Wright et al. (2012) as constituting an elevated and/or differentiated profile. In addition to the SSM parameters, dominance and affiliation vector scores are computed using trigonometrically weighted combinations of octant correlations (Gurtman & Pincus, 2003).
The IPC and interpersonal theory have been used in this way to examine the construct validity of a wide range of measures assessing dozens of personality and clinical constructs (e.g., Gallo & Smith, 1998; Gurtman, 1991, 1992, 1993, 1996, 1997, 1999; Hill, Zrull, & Turlington, 1997; Hopwood, Ansell, et al., 2011; Pincus & Wiggins, 1990; Pincus & Wilson, 2001; Wiggins & Broughton, 1991; Wiggins & Pincus, 1989; Wright et al., 2012; Wu et al., 2015). Although the SSM provides a parsimonious summary of a complex profile of correlations, it is predominately descriptive in nature. Recently, however, Zimmermann and Wright (2017) have developed a novel bootstrapping methodology for computing confidence intervals around IPC SSM parameters, allowing researchers to determine whether external measures’ profiles are statistically distinct from each other. This bootstrapping procedure is a promising method for moving the interpersonal paradigm of personality assessment from pure description to providing a framework for testing inferential questions.
Interpersonal Analyses of the Dark Triad
Because many of the deficits associated with the Dark Triad are interpersonal in nature, the IPC is one way that researchers can conceptualize and distinguish these traits. Research also suggests that the pattern of associations between traits and interpersonal characteristics varies depending on the interpersonal surface used (Miller, Price, Gentile, Lynam, & Campbell, 2012). Additionally, a multisurface approach to interpersonal assessment of individual patients provides a rich portrait of personality dynamics (Dawood & Pincus, 2016; Hopwood, Pincus, & Wright, in press; Pincus, Sadler, et al., 2014). Thus, concurrently using multiple interpersonal surfaces allows investigators to conceptualize Dark Triad traits within and across surfaces, providing a comprehensive interpersonal analysis that examines the distinctiveness of Dark Triad traits and their construct validity.
Prior research on the interpersonal nature of the Dark Triad has typically focused on assessing the association between a single trait and a single IPC surface. Self-report measures of psychopathy given to both adolescents and adults are located in Quadrant II of the IPC, characterized by high dominance and low affiliation, on the traits, values, and motives surfaces (Blackburn & Maybury, 1985; Hicklin & Widiger, 2005; Salekin, Leistico, Trobst, Schrum, & Lochman, 2005; Salekin, Trobst, & Krioukova, 2001). Machiavellianism demonstrates similar associations on the interpersonal traits and values surfaces (Gurtman, 1992; Jones & Paulhus, 2009; Trapnell & Paulhus, 2012; Wiggins & Broughton, 1985). Narcissism, measured using the Narcissistic Personality Inventory (Raskin & Hall, 1979), also projects onto Quadrant II of the IPC, showing a weak negative association with affiliation and a positive association with dominance on the traits and problems surfaces (Bradlee & Emmons, 1992; Hopwood, Pincus, DeMoor, & Koonce, 2008; Jones & Paulhus, 2011; Locke, 2000; Pincus et al., 2009; Ruiz, Smith, & Rhodewalt, 2001). Although these studies provide information about each Dark Triad trait individually, they do not allow for empirical comparisons between Dark Triad traits.
Only a handful of studies have simultaneously located all three Dark Triad traits on the traits surface (Jones & Paulhus, 2011; Rauthmann & Kolar, 2013). In these two studies, psychopathy was consistently associated with hostile dominant traits, while Machiavellianism was associated with either hostile–dominant traits or hostile–submissive traits. Compared to Machiavellianism and psychopathy, narcissism was consistently associated with greater dominance and less hostility.
Current Study
The purpose of this study is to examine the interpersonal nature of Dark Triad traits using multisurface interpersonal assessment and a new bootstrapping methodology for computing SSM confidence intervals (CIs). This will be accomplished with the following five steps: (1) computing and locating the CIs for narcissism, psychopathy, and Machiavellianism on the interpersonal problems, interpersonal sensitivities, interpersonal values, and interpersonal efficacies surfaces; (2) examining gender differences in associations across measures and surfaces; (3) determining whether the structural summary parameters for narcissism, psychopathy, and Machiavellianism are statistically distinct within each surface providing evidence of discriminant validity; (4) determining whether the structural summary parameters for IA, SRP-III, and Short Dark Triad (SD3) Psychopathy scale are statistically convergent within each surface providing evidence of convergent validity; and (5) substantively integrating the information across IPC surfaces to examine the personality dynamics associated with each Dark Triad trait.
Based on previous research and theory, we hypothesize the following:
Method
Participants
Participants were 653 undergraduate students ranging in age from 18 to 42 (M = 19.28, SD = 11.68) at a large northeastern university who were recruited through a psychology department subject pool for course credit. A total of 91 students (13.94%) generated incomplete or invalid protocols based on the following criteria: (1) the number of missing items was more than 10% of the items in the questionnaire (n = 16) or (2) the score on the Personality Assessment Inventory Infrequency Scale was more than 2.5 SDs above the mean in a normative sample (n = 75; Morey, 1991). Overall, 562 valid protocols were retained for analysis. A total of 49.3% of these participants were male, and 50.7% were female.
Dark Triad Measures
Short Dark Triad
The SD3 (Jones & Paulhus, 2014) is a 27-item self-report measure of Machiavellianism, psychopathy, and narcissism. Items are rated on a 5-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). In the current study, Cronbach’s α for Machiavellianism, psychopathy, and narcissism were .78, .74, and .71, respectively. Although this measure was developed recently, there is significant research demonstrating convergent validity with longer measures of the Dark Triad traits, including the MACH-IV (Christie & Geis, 1970), the SRP-III (Paulhus et al., in press), and Narcissistic Personality Inventory (Raskin & Hall, 1979), as well as concurrent validity with a number of maladaptive outcomes (Baughman et al., 2012; Giammarco, Atkinson, Baughman, Veselka, & Veron, 2013; Jones & Paulhus, 2014; Lee et al., 2013).
Self-Report Psychopathy Scale
The SRP-III (Paulhus et al., in press) is a 64-item self-report measure of psychopathic traits. Items are rated on a 5-point Likert scale ranging from 1 (disagree strongly) to 5 (agree strongly). In the current study, the measure exhibited strong internal consistency with an overall scale Cronbach’s α of .91. The SRP-III has also shown strong convergent and discriminate validity across multiple studies (Mahmut, Homewood, & Stevenson, 2008; Mahmut, Menictas, Stevenson, & Homewood, 2011; K. M. Williams et al., 2003; K. M. Williams, Paulhus, & Hare, 2007).
Multidimensional Personality Questionnaire
The MPQ-BF (Patrick, Curtin, & Tellegen, 2002) is a 155-item self-report measure of 11 normal range personality traits that can be used to assess psychopathy (Benning et al., 2005). Rather than computing psychopathy scores using regression weights as indicated in Benning et al. (2003), Blonigen, Hicks, Krueger, Patrick, and Iacono (2006) identified a subset of 58 items from the MPQ-BF that can be used to compute psychopathy scores, resulting in essentially the same findings as the regressions weights while using substantially fewer items. A total of 24 items comprise the FD scale, pulling 17 items from the three MPQ traits identified by Benning et al. (2003) as being uniquely predictive of FD, social potency (+), stress reaction (−), and harm avoidance (−; Blonigen et al., 2006). A total of 34 items comprise the IA scale, pulling 32 items from 4 of the 5 MPQ traits that Benning et al. (2003) identified as being uniquely predictive of IA, alienation (+), aggression (+), control (−), and traditionalism (−; Blonigen et al., 2006). Items are rated as either True or False. In the current study, both MPQ-estimated FD and IA demonstrate good internal consistency with alphas of .76 and .76, respectively.
Interpersonal Circumplex Measures
Inventory of Interpersonal Problems Short Circumplex (IIP-SC)
The IIP-SC (Soldz et al., 1995) is a 32-item measure that maps interpersonal problems (distressing behavioral excesses and inhibitions) onto the 8 octants of the IPC. Items are rated on a 5-point Likert scale ranging from 0 (not at all) to 4 (extremely). In the current study, Cronbach’s α for each octant ranged from .63 (PA and BC) to .87 (FG) with a mean α of .76. Research indicates that the IIP-SC can reliably differentiate college students from clinical patients and has been extensively validated in personality and clinical research (e.g., Gurtman, 1996; Hopwood et al., 2008; McEvoy, Burgess, Page, Nathan, & Fursland, 2013; Pincus & Wiggins, 1990; Sodano & Tracey, 2011; Soldz et al., 1995).
Interpersonal Sensitivities Circumplex (ISC)
The ISC (Hopwood, Ansell, et al., 2011) is a 64-item measure that maps interpersonal irritants and sensitivities (bothersome behaviors enacted by others) onto the 8 octants of the IPC. Items are rated using an 8-point Likert scale ranging from 1 (not at all, never bothers me) to 8 (extremely, always bothers me). In the current study, Cronbach’s α for each octant ranged from .71 (LM) to .89 (DE) with a mean α of .81. Initial evidence supports the circumplex structure and criterion validity of the ISC (Hopwood, Ansell, et al., 2011; T. F. Williams, Thomas, Donnellan, & Hopwood, 2014).
Circumplex Scales of Interpersonal Values (CSIV)
The CSIV (Locke, 2000) is a 64-item measure that maps interpersonal values (the importance that one enacts certain interpersonal behaviors or has certain interpersonal experiences) onto the 8 octants of the IPC. Items are rated on a 5-point Likert scale ranging from 0 (not important to me) to 4 (extremely important to me). In the current study, Cronbach’s α for each octant ranged from .73 (PA) to .85 (LM) with a mean α of .80. Research shows the CSIV to have a robust circumplex structure and supports its construct validity (Acton & Revelle, 2002; Locke, 2003; Locke & Christensen, 2007; Locke, Craig, Baik, & Gohil, 2012; Thomas, Kirchmann, Suess, Bräutigam, & Strauss, 2012).
Circumplex Scales of Interpersonal Efficacies (CSIE)
The CSIE (Locke & Sadler, 2007) is a 32-item measure that maps interpersonal efficacies (confidence in one’s ability to enact certain interpersonal behaviors) onto the 8 octants of the IPC. Items are rated on an 11-point Likert scale ranging from 0 (I am not at all confident that) to 10 (I am absolutely confident that). In the current study, Cronbach’s α for each octant ranged from .61 (HI) to .82 (PA) with a mean α of .71. Research shows the CSIE conforms to a circumplex model and demonstrates convergent validity with other circumplex surfaces (Locke & Sadler, 2007), and it is sensitive to change in psychotherapy (Sayegh et al., 2012).
Validity Scale
The Personality Assessment Inventory Infrequency Scale (Morey, 1991) is an 8-item scale from the Personality Assessment Inventory, which assesses inattention and carelessness on the part of the participant. Items are rated on a 4-point Likert scale ranging from 0 (false, not at all true) to 3 (very true).
Procedure
Participants completed all measures online using a standardized web-based interface (SurveyMonkey). Participants received course credit for their participation.
Data Analysis
Data analyses were completed in two steps. In the first step, the well-established SSM (Gurtman, 1992; Gurtman & Pincus, 2003) was used to calculate the R2, elevation, amplitude, and angular displacement for the SD3 Dark Triad scales, the SRP-III total score, FD, and IA. This procedure was repeated for the problems, sensitivities, values, and efficacies IPC surfaces. The bootstrapping methodology developed by Zimmermann and Wright (2017) was used to compute CIs around these parameters. Although the SSM is well established, the use of CIs provides an objective and quantitative means for determining whether IPC profiles are distinct. Probability estimates for the CIs in this particular sample are reported. These estimates quantify the probability that the CIs associated with the amplitude, and angular displacement parameters are accurate in a given data set. Zimmermann and Wright (2017) suggest that the CIs for amplitude and angular displacement should not be interpreted when the probability estimate is less than .50, should be interpreted with caution when probability estimates are between .50 and .95 as estimates might be biased to some extent, and should be interpreted confidently when probability estimates are greater than .95. In the second step, within-surface interpersonal profiles were statistically compared by creating CIs around the differences in structural summary parameters using syntax developed for the R statistical platform (Zimmermann & Wright, 2017). This procedure was used to determine whether, on each IPC surface, (a) criterion measures were associated with similar interpersonal characteristics for men and women and (b) criterion measures had statistically distinct SSM parameters.
Results
Table 1 presents the means, standard deviations, and range of responses for the SD3 scales, the SRP-III Total Score, FD, and IA for the sample as a whole, men, and women. Men scored significantly higher than women on SD3 Machiavellianism, SD3 psychopathy, SD3 narcissism, the SRP-III, and FD. Mean scores for men and women on IA were not significantly different from each other.
Descriptive Statistics for Dark Triad Traits.
Note. SD3 = Short Dark Triad; MACH = Machiavellianism; NAR = narcissism; PSYCH = psychopathy; SRP-III = Self-Report Psychopathy Scale; FD = Fearless Dominance; IA = Impulsive Antisociality. N = 560 for the SD3 scales; N = 562 for the SRP-III, FD, and IA; N = 285 for women across all measures; N = 275 for men for the SD3 scales; N = 277 for men for the SRP-III, FD, and IA.
Indicates that the means for men and women were significantly different from each other, p < .01.
Structural Summary Parameters and Confidence Intervals
Table 2 contains the structural summary parameters, and the associated 95% bootstrapped CIs for each of the SD3 scales and the three additional measures of psychopathy on each of the four IPC surfaces. Visual representations of the CIs for the amplitude (radial CI) and the angular displacement (angular CI) can be found in Figure 3. Note that Figure 3 does not contain a visual representation of the CIs for elevation. In the current sample, probability estimates indicate that the CIs around the amplitude and angular displacement parameters associated with IA and SD3 Machiavellianism on the interpersonal sensitivities surface should be interpreted with caution as they might be biased to some extent. The remaining scales on each surface have probability estimates greater than .95, indicating that the CIs for amplitude and angular displacement are highly accurate.
Structural Summary Parameters, 95% Bootstrap Confidence Intervals, and Probability Estimates for Dark Triad Traits.
Note. IIP-SC = Inventory of Interpersonal Problems Short Circumplex; SD3 = Short Dark Triad; MACH = Machiavellianism; NAR = narcissism; PSYCH = psychopathy; SRP-III = Self-Report Psychopathy Scale; FD = Fearless Dominance; IA = Impulsive Antisociality; ISC = Interpersonal Sensitivities Circumplex; CSIV = Circumplex Scales of Interpersonal Value; CSIE = Circumplex Scales of Interpersonal Efficacies. Numbers in brackets represent the 95% confidence interval for the associated structural summary parameter.
Amplitude and angular displacement confidence intervals for Dark Triad traits across surfaces.
Interpersonal Problems
R2 values for all criterion variables indicated that profiles were prototypical in nature. Thus, along with elevation, the amplitude and angular displacement parameters can also be interpreted. Amplitude values across scales suggested that these scales are uniquely associated with particular interpersonal problems more so than others. Among the SD3 scales, angular displacement values ranged from 83.60° (narcissism) to 158.67° (Machiavellianism), suggesting that these traits are characterized by domineering (PA), vindictive (BC), and cold (DE) interpersonal problems. Among the psychopathy scales, angular displacement values ranged from 73.15° (FD) to 133.84° (SRP-III), suggesting that high scores on these measures are associated with domineering (PA) and vindictive (BC) interpersonal problems. Parameter values for elevation suggest that IA is associated with significant interpersonal distress, while FD is associated with a notable lack of interpersonal distress.
Interpersonal Sensitivities
On the sensitivities surface, R2 values suggest that profiles were prototypical for all criterion variables except SD3 narcissism and IA. SD3 narcissism and IA appear to have more complex profiles and, therefore, their associated amplitude and angular displacement parameters are not interpreted. Among the remaining scales, SD3 psychopathy and SRP-III total score appear to be uniquely associated with sensitivity to certain bothersome behaviors more so than others. Among the SD3 scales, interpretable angular displacement values ranged from 302.06° (psychopathy) to 339.27° (Machiavellianism), suggesting that these traits are associated with sensitivities to dependence (JK) and affection (LM), respectively. Among the psychopathy scales, interpretable angular displacement values ranged from 272.39° (FD) to 315.28° (SRP-III), suggesting sensitivities to passivity (HI) and dependence (JK). The elevation parameter associated with IA suggests an association with general interpersonal sensitivity or misanthropy.
Interpersonal Values
On the values surface, R2 values suggest that the profiles associated with these measures were prototypical in nature, allowing for the interpretation of all amplitude and angular displacement parameters. Amplitude values associated with the three SD3 scales, the SRP-III total score, and FD indicate that these scales were uniquely associated with attaching importance to specific behaviors more so than others. Among the SD3 scales, angular displacement values ranged from 95.46° (narcissism) to 162.92° (Machiavellianism), suggesting that these traits are associated with agentic (PA) and distant (DE) interpersonal values. Among the psychopathy scales, angular displacement values ranged from 65.50° (FD) to 167.94° (IA), suggesting that these psychopathy scales are associated with agentic and communal (NO) and distant (DE) interpersonal values. The elevation parameter associated with SD3 Machiavellianism suggested that these individuals generally have diffuse interpersonal goals.
Interpersonal Efficacies
On the efficacies surface, R2 values for all criterion variables suggest that the profiles associated with these measures were prototypical in nature, allowing for the interpretation of the amplitude and angular displacement parameters. Amplitude values on the efficacies surface suggest that all of the criterion scales were uniquely associated with certain interpersonal efficacies more so than others. Among the SD3 scales, angular displacement values ranged from 80.47° (narcissism) to 165.43° (Machiavellianism), suggesting that the three SD3 scales are associated with dominant (PA), dominant and distant (BC), and distant (DE) interpersonal efficacies. Among the psychopathy scales, angular displacement values ranged from 68.56° (FD) to 143.95° (SRP-III), suggesting that these scales are associated with dominant (PA) and dominant and distant (BC) interpersonal efficacies. Elevation parameters associated with SD3 narcissism and FD indicate that these constructs are associated with feeling generally more socially efficacious than the average person.
Gender Comparisons and Difference Confidence Intervals
Table 3 contains the structural summary parameters for men and women and the differences among those parameters for all criterion variables on the problems, sensitivities, values, and efficacies surfaces. Of the 120 comparisons, only 3 comparisons suggest significant differences in parameter values between men and women. As this is less than would be expected due to chance alone, gender was not considered in the following scale comparisons, and the combined sample was again employed.
Gender Differences in Structural Summary Parameters With 95% Confidence Intervals for Dark Triad Traits.
Note. IIP-SC = Inventory of Interpersonal Problems Short Circumplex; SD3 = Short Dark Triad; MACH = Machiavellianism; NAR = narcissism; PSYCH = psychopathy; SRP-III = Self-Report Psychopathy Scale; FD = Fearless Dominance; IA = Impulsive Antisociality; ISC = Interpersonal Sensitivities Circumplex; CSIV = Circumplex Scales of Interpersonal Value; CSIE = Circumplex Scales of Interpersonal Efficacies. Dif. = difference. Items in bold represent parameters on which men and women differ (CIs do not contain 0).
Construct Comparisons and Difference Confidence Intervals
Table 4 contains the differences among structural summary parameters associated with each Dark Triad scale and the associated 95% bootstrapped CIs for each difference on each of the four surfaces.
Structural Summary Parameters With 95% Confidence Intervals for Differences of Dark Triad Scales.
Note. IIP-SC = Inventory of Interpersonal Problems Short Circumplex; SD3 = Short Dark Triad; MACH = Machiavellianism; NAR = narcissism; PSYCH = psychopathy; SRP-III = Self-Report Psychopathy Scale; FD = Fearless Dominance; IA = Impulsive Antisociality; ISC = Interpersonal Sensitivities Circumplex; CSIV = Circumplex Scales of Interpersonal Value; CSIE = Circumplex Scales of Interpersonal Efficacies. Values represent the degree to which the second trait listed differs from the first trait. Items in bold represent parameters on which the compared traits differ (CIs do not contain 0).
Interpersonal Problems
Cross-construct comparisons of the SD3 scales identify a number of differences among Dark Triad traits. Although the three scales are not significantly different from each other in terms of amplitude, they do differ in terms of angular displacement, indicating that each is associated with a different interpersonal theme. Dominance scores are significantly lower for Machiavellianism than they are for either psychopathy or narcissism. Affiliation scores are significantly higher for narcissism than for either Machiavellianism or psychopathy. In terms of the elevation parameter, narcissism is associated with significantly less interpersonal distress than either Machiavellianism or psychopathy.
Within-construct comparisons of the four psychopathy scales also identifies points of similarity and difference. Although SD3 psychopathy, the SRP-III, and FD exhibit similar amplitude parameters, IA is significantly less differentiated than SD3 psychopathy and the SRP-III. In terms of angular displacement, each psychopathy scale projects onto a significantly different location on the problems surface. Although the measures do not differ from one another in terms of dominance, they each occupy a unique position on the affiliation dimension. Affiliation is greatest for FD and decreases as one moves to IA, SD3 psychopathy, and the SRP-III. FD is also associated with significantly lower elevation and thus less interpersonal distress than the other measures of psychopathy. Conversely, IA has a significantly higher elevation parameter relative to the other three measures, indicating that IA is associated with significantly more interpersonal distress than the other psychopathy scales.
Interpersonal Sensitivities
As noted previously, it is important to interpret comparisons involving SD3 Machiavellianism with caution due to potential bias in the estimation of the CIs. Cross-construct comparisons indicate that each SD3 scale is associated with a significantly different angular displacement parameter, indicating that each trait is associated with a different predominant interpersonal sensitivity. Machiavellianism is significantly more sensitive to dominance, while narcissism is significantly less sensitive to affiliation compared to the other SD3 scales. Additionally, SD3 Machiavellianism exhibits a significantly higher elevation parameter and lower amplitude parameter than narcissism and psychopathy, suggesting an association with general interpersonal sensitivity (misanthropy) and little substantive differentiation.
Within-construct comparisons of the four Psychopathy scales highlights points of similarity and difference. Once again, comparisons that involve IA should be interpreted with caution. In terms of angular displacement, SD3 psychopathy, FD, and the SRP-III all project onto significantly different locations. Sensitivity to affiliation decreases as one moves from the SRP-III to SD3 psychopathy to FD. The SRP-III is also significantly more sensitive to affiliation than IA. IA is significantly more sensitive to dominance than the other three measures of psychopathy. In terms of elevation, FD has a significantly lower elevation value compared to the SRP-III, SD3 psychopathy, and IA and a significantly lower amplitude parameter than the SRP-III. This suggests that FD is associated with significantly less general interpersonal sensitivity (misanthropy) overall and is less differentiated than the SRP-III. Conversely, IA is significantly more elevated and less differentiated than the other psychopathy scales.
Interpersonal Values
Cross-construct comparisons of the SD3 scales find that narcissism has a significantly different angular displacement parameter than both Machiavellianism and psychopathy, indicating significant differences in interpersonal theme. Narcissism was more strongly associated with valuing both dominance and affiliation than other SD3 scales. Although Machiavellianism and psychopathy did not differ significantly in terms of angular displacement, Machiavellianism had a stronger association with affiliation than psychopathy. Machiavellianism also had a significantly higher elevation parameter than both narcissism and psychopathy, indicating the Machiavellianism is associated with having more diffuse interpersonal goals. Psychopathy was significantly more differentiated in terms of interpersonal values than both Machiavellianism and narcissism.
Within-construct comparisons of the four psychopathy scales indicate that FD is projected onto a significantly different location than SD3 psychopathy, the SRP-III, and IA. FD is associated with valuing both dominance and affiliation more than the other psychopathy scales. Additionally, IA is associated with valuing dominance less than the other three measures and affiliation more than the SRP-III and SD3 psychopathy scale. In terms of elevation, FD is significantly less elevated relative to the other psychopathy measures, suggesting that FD is associated with more specific interpersonal goals. Conversely, IA is significantly more elevated relative to the other measures of psychopathy, indicating that IA is associated with more diffuse interpersonal goals. Additionally, both FD and IA are significantly less differentiated than SD3 psychopathy and the SRP-III as evidenced by significant differences on the amplitude parameter.
Interpersonal Efficacies
Cross-construct comparisons indicate that all SD3 scales significantly differ from each other in terms of angular displacement, indicating each trait is associated with a distinct interpersonal theme. SD3 narcissism was more strongly associated with feeling effective enacting both dominance and affiliation compared to Machiavellianism. Psychopathy was more strongly associated with feeling effective enacting dominance than Machiavellianism. Additionally, SD3 narcissism has a significantly higher elevation parameter than other SD3 traits, indicating greater feelings of efficacy in the interpersonal situations. Although Machiavellianism had a significantly higher elevation than psychopathy, indicating greater feelings of interpersonal efficacy, it was significantly less differentiated in terms of interpersonal efficacies compared to both psychopathy and narcissism.
Within-construct comparisons of the four Psychopathy scales indicate that FD projects onto a significantly different location than other measures of psychopathy such that FD is associated with significantly greater confidence enacting both dominance and affiliation. Additionally, IA is associated with feeling less confident enacting dominance and more confident enacting affiliation than SD3 psychopathy and the SRP-III. In terms of elevation, FD is significantly more elevated relative to the SRP-III, SD3 psychopathy, and IA, suggesting that FD is associated with greater feelings of interpersonal effectiveness relative to other measures of psychopathy. Conversely, IA is significantly less elevated relative to the SRP-III and less differentiated than all other psychopathy measures as evidenced by significant differences on the amplitude parameter.
Discussion
This study used multisurface interpersonal assessment and a novel bootstrapping methodology to create CIs around the circumplex, SSM parameters associated with the SD3 scales, and three additional measures of psychopathy. CIs were computed around the difference between SSM parameters values for men and women to examine the statistical significance of gender differences across measures. Finally, differences of CIs were also computed to determine whether individual scales were statistically distinct from one another, providing evidence for convergent and/or discriminant validity.
Gender Differences
As hypothesized, men scored significantly higher than women on all Dark Triad traits except for IA. These results are consistent with prior work, which found significant mean-level differences in Dark Triad traits for men and women (Jonason et al., 2009; Jonason, Li, & Buss, 2010; Paulhus & Williams, 2002). CIs were then computed around the structural summary parameters to determine whether the parameters for men and women were statistically distinct. Findings indicate that there were very few (2.5%) significant structural summary parameter differences, suggesting that these traits function interpersonally in the same way for men and women. These results provide support for Hypothesis 4 and are consistent with previous work demonstrating that men and women exhibit similar Dark Triad trait correlations with the Big Five personality traits, measures of cognitive ability, measures of self-enhancement, and mate retention and poaching tactics (Jonason et al., 2009; Jonason, Li, & Buss, 2010; Paulhus & Williams, 2002). Although it has not been directly examined in the literature, this consistent pattern of findings (mean-level differences but similar associations with criterion variables) may be explained by measurement noninvariance, that is, distinct quantitative relationships between observed test items and the latent trait for men and women (Widaman & Reise, 1997). In particular, future research should examine whether perhaps these and other Dark Triad measures meet weak rather than strong gender invariance assumptions.
Construct Validity of the SD3
Structural summary parameters associated with the SD3 Machiavellianism, narcissism, and psychopathy scales were computed for the interpersonal problems, sensitivities, values, and efficacies circumplex surfaces. Although the relative positioning of Dark Triad traits is similar to that reported in previous research (Jones & Paulhus, 2011; Rauthmann & Kolar, 2013; T. F. Williams & Simms, 2016), the current study advances these prior descriptive investigations by providing statistical comparisons of the SD3 scales using a new method to compute CIs. Of the 60 (3 pairwise comparisons × 5 parameters × 4 surfaces) comparisons made, 42 (70%) were statistically significant. In particular, angular displacement values, which identify the dominant interpersonal theme associated with each SD3 scale, were significantly different from one another 92% of the time, providing support for Hypothesis 1. In fact, the only time that SD3 scales did not exhibit distinct angular displacements was for Machiavellianism and psychopathy when compared on the interpersonal values surface. It was always the case that SD3 scales on a given surface differed from one another by at least two of the five SSM parameters, indicating that although significant differences were less consistent for the other four SSM parameters across surfaces, they were still prevalent. Thus, the use of CIs provides support for the discriminant validity of Machiavellianism, narcissism, and psychopathy as assessed by the SD3. These findings suggest that a composite measure of Dark Triad traits might overlook the unique interpersonal characteristics associated with each Dark Triad trait individually. Given that the SD3 is a relatively new and short measure of Dark Triad traits, these findings provide initial support for its use in future Dark Triad research.
Psychopathy Measures
In addition to determining whether different constructs have different interpersonal characteristics (discriminant validity), SSM CIs also allow researchers to examine whether different measures of the same construct have statistically similar interpersonal characteristics (convergent validity). SSM parameters associated with SD3 psychopathy, the SRP-III total score, and MPQ-assessed FD and IA were computed for the problems, sensitivities, values, and efficacies surfaces. CIs were then computed to determine whether parameters were statistically different from one another. Of the 60 (3 pairwise comparisons × 5 parameters × 4 surfaces) comparisons made between the SRP-III, SD3, and IA, 34 (57%) were statistically significant. Angular displacement values significantly differed 33.3% of the time. Examination of pairwise comparisons, however, suggests that the SRP-III and SD3 psychopathy scales have similar interpersonal characteristics 80% of the time. One possible explanation for this difference is that the SRP-III and SD3 psychopathy scales were created to assess psychopathy specifically, while IA was computed from a subset of items drawn from the MPQ, a measure of normal range personality. Consistent with current findings, previous research suggests that measures designed to specifically assess psychopathy or antisocial behavior typically fall in the hostile–dominant (BC) octant of the IPC, appearing in visually similar locations (Jones & Paulhus, 2014; Salekin et al., 2001). Although MPQ-estimated psychopathy factors have demonstrated good criterion and construct validity in past research (Benning et al., 2005; Witt & Donnellan, 2008), it is possible that the interpersonal content of the MPQ-derived scales differs from that in more traditional measures of psychopathy. In particular, the greater prevalence of items related to interpersonal warmth (DeYoung, Weisberg, Quilty, & Peterson, 2013; Hopwood, Burt, Keel, Neale, Boker, & Klump, 2011) may explain why IA is often statistically distinct from more traditional measures of psychopathy. The current results call into question the construct validity of the MPQ-derived psychopathy dimensions and support using measures specifically developed to measure psychopathy, such as the SRP-III and SD3.
Consistent with Hypothesis 2b, of the 60 (3 pairwise comparisons × 5 parameters × 4 surfaces) comparisons made between FD and the other psychopathy scales, 46 (76.7%) were statistically significant, and angular displacement values significantly differed 91.7% of the time. Thus, FD appears to have distinct interpersonal characteristics when compared to other measures of psychopathic traits. Additionally, FD was associated with low-interpersonal distress and high-interpersonal efficacy, ratings that are generally associated with more adaptive functioning. These findings are consistent with meta-analytic findings by Miller and Lynam (2012) that highlight the distinct adaptive nature of FD, including negative relationships with neuroticism, internalizing symptoms, and behavioral inhibition; positive relationships with positive emotionality, extraversion, assertiveness, and sensation seeking; and small to no relationship with antagonism, empathy, aggression, substance use, and so on, constructs that are normally associated with measures of psychopathy.
Cross-Surface Integration of the Dark Triad
Although looking at a single IPC surface is a useful way to examine the interpersonal distinctiveness of external measures, examination of the dominant interpersonal themes across IPC surfaces provides a more comprehensive portrait of the unique personality dynamics associated with each trait, consistent with Hypothesis 3 (Dawood & Pincus, 2016; Hopwood et al., in press).
SD3 Machiavellianism
High scores on Machiavellianism are associated with cold interpersonal problems, characterized by difficulty expressing affection and love toward others, making long-term commitments to other people, and getting along with and forgiving others. High Machiavellianism is not only associated with difficulty expressing affection but also with being bothered by others expressing affection and acting in warm and familiar ways. Machiavellianism is also associated with valuing appearing detached and guarded and concealing one’s thoughts and feelings from others, and efficacy doing so. Machiavellianism is associated with the ability to be cold, unfriendly, tough, and even cruel when needed. High scorers are capable of convincing others to leave them alone.
SD3 Psychopathy
High scores on SD3 psychopathy are associated with vindictive interpersonal problems, characterized by both a general distrust of others and an inability to care about their needs and happiness. High-scoring individuals not only don’t care about the needs of others, they are also sensitive to dependence, finding it bothersome when others rely on, defer, or cling to them. Like those high on Machiavellianism, individuals scoring high on psychopathy value concealing their thoughts and feelings from others and appearing guarded and detached. Unlike those high on Machiavellianism, individuals scoring high on psychopathy report efficacy at being aggressive rather than cold and are able to keep the upper hand and win arguments when needed.
SD3 Narcissism
High scores on narcissism are associated with domineering interpersonal problems characterized by a controlling and manipulative approach often in an effort to influence and change other people. Individuals high on narcissism not only report that they are controlling but also report being bothered by submissiveness and passivity in others (i.e., people who are easily able to be manipulated or controlled). Perhaps this reflects the devaluation of others and entitled justifications for manipulation commonly discussed in the clinical literature on narcissism (e.g., Kernberg, 2007). High narcissism scores are associated with valuing appearing confident around others, being perceived as an authority, and preventing others from bossing one around. Such individuals both value these behaviors and report efficacy enacting them, indicating that they can be forceful and assertive and can take charge and speak up when they have something to say.
Personality Dynamics
Although SD3 Machiavellianism, psychopathy, and narcissism exhibit distinct interpersonal themes (cold, aggressive, and controlling, respectively), similar underlying dynamics undergird the relationship between surfaces. In Figure 3, consideration of the problems and sensitivities surfaces suggests that one’s self-identified problematic behaviors are often directly opposite (180°) of the behaviors identified as bothersome when enacted by others. This suggests that individuals are bothered most by those least like themselves. These findings are consistent with previous research by Hopwood, Ansell, et al. (2011), suggesting that interpersonal opposites are generally perceived aversively. In contrast to the oppositeness that characterizes the relationship between the problems and sensitivities surfaces, sameness characterizes these parameters on the values and efficacies surfaces. Thus, the interpersonal behaviors that are valued for each trait are also the behaviors that are identified as the most confidently enacted. Interestingly, these same behaviors that are valued and enacted effectively are also often the behaviors that are identified as problematic, suggesting that perhaps respondents are aware of the social costs associated with their dark personality traits.
Limitations, Future Directions, and Conclusions
One limitation of this study was the exclusive use of self-report in the assessment of Dark Triad traits. A substantial literature exists on the degree of self-other agreement for both personality disorders and more general personality traits, suggesting median correlations of .36 across the 10 DSM-IV defined PDS (Klonsky, Oltmanns, & Turkheimer, 2002) and correlations of .40 to .47 when five-factor model personality traits were considered (McCrae et al., 2004). When Dark Triad traits themselves have been examined, researchers found that self- and informant reports of the SD3 scales were correlated .34 for narcissism, .42 for Machiavellianism, and .57 for psychopathy (Jones & Paulhus, 2014). Researchers have also found that when informants knew the participant well, self-other correlations across a number of psychopathy scales ranged from .34 to .83 (Miller, Jones, & Lynam, 2011). Thus, self-other correlations for Dark Triad traits appear to be comparable to correlations associated with personality traits more broadly. Future work might make a finer-grained examination of differences in structural summary parameters when self- and informant ratings are considered, or when different methodologies (interviews vs. self-report) are used in data collection.
Despite this limitation, the current study is one of the first to use SSM CIs (Zimmermann & Wright, 2017) to statistically test theoretically important differences in interpersonal profiles of dark personality traits. Given that point estimates are often biased and the use of CIs has been a recommended practice in psychology journals for the past 15 years (Wilkinson & Task Force on Statistical Inference, 1999), the bootstrap extension is an important methodological advance within the SSM approach to interpersonal construct validation. Although past research has relied heavily on visual inspection of a single IPC surface when interpreting findings, future work can take advantage of this new methodology to move interpersonal construct validation from the descriptive to the inferential, and it can employ the multisurface assessment approach to provide enhanced interpersonal portraits of personality scales and constructs.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.