1. Introduction
The dark triad refers to a personality configuration mainly characterized by the presence of three specific traits: Machiavellianism, narcissism, and psychopathy [
1]. Researchers have justified the grouping of these factors by highlighting that all three traits imply a socially malevolent character with behavioral tendencies toward self-promotion, emotional coldness, duplicity, and aggressiveness (p. 557); thus, they constitute a personality type associated with serious problems or social maladjustments in adults, such as financial fraud [
2], bullying or cyberbullying [
3,
4], and inappropriate behaviors at work [
5,
6].
To measure the constructs that comprise the dark triad, specific scales from broader instruments have been used for psychopathy [
7,
8], Machiavellianism [
9], and narcissism [
10,
11]. For evaluation, these scales require completing long questionnaires to acquire a final and precise measurement of the dark triad components. To facilitate the joint measurement of the three constructs, two brief questionnaires that facilitate the simultaneous estimation of these three dimensions have been developed. These questionnaires—the Dirty Dozen [
12] and Short Dark Triad [
13]—have been widely disseminated and supported at an international level.
The Dirty Dozen is the shorter of the two instruments, comprising only four items for each dimension of the dark triad. Various authors have indicated that this brevity does not fully capture the characteristics of the dark triad traits [
14,
15,
16] despite some reports pointing to the good reliability of this instrument [
17,
18]. Considering the limitations of the Dirty Dozen, Jones and Paulhus [
13] developed the SD3 as a valid and reliable instrument for measuring dark triad traits. This scale consists of 27 statements, 9 for each of the constructs, which are rated on a Likert-type scale with five responses. Jones and Paulhus presented five different studies for validating the scale, including information on the validation of its subscales.
The analysis involving a comparison of both instruments (DD-SD3) highlighted the greater convergence and incremental validity of the SD3 in terms of longer and more established measures of the dark triad traits, adequate discriminant validity, and criterion validity concerning the traits of the five-factor model [
19]. Due to these superior psychometric properties, the SD3 has been widely propagated worldwide [
3,
20,
21], including adaptations and their analyses in countries as diverse as Germany [
22], Argentina [
23], China [
24], Poland [
25], Croatia [
26], Russia [
27], Iran [
28], Japan [
29], Taiwan [
30], Holland [
31], Serbia [
32], Thailand [
33], France [
34], Turkey [
35], and Spain [
36].
Although several studies have involved psychometric analyses of the SD3 in different adult populations, studies on dark triad traits in the adolescent population are scarce, primarily due to the lack of adaptation and validation of this instrument for this age group. Studies on the adaptation of the SD3 in the Italian adolescent population indicate good reliability of the original unmodified scale [
37], while disparate results have been obtained regarding Russian adolescents [
38], with items that can be associated with more than one factor (especially in the psychopathy dimension). To date, the only attempts to adapt the original scale for minors were conducted in an excessively small sample of Polish adolescents [
39] and a sample of Portuguese adolescents in disadvantaged and impoverished zones in the Lisbon area [
40].
In the study carried out among Polish adolescents, the scale was refined through several adjustments considering various criteria, namely through the arbitrary elimination of one of its items (“I enjoy having sex with people I hardly know”), internal validation based on statistical criteria, and external validation based on the correlation found between other instruments that do not estimate the presence of dark traits such as the Big Five Personality Test, the Buss–Perry Aggression Questionnaire, or the Rosenberg Self-Esteem Scale. The final solution proposed by the authors of 25 items has not been validated for the adolescent population, nor are there any reliability or descriptive results regarding its application to the adolescent population. For the Portuguese adaptation of the Short Dark Triad, researchers started from all the items on the scale based on exclusively statistical criteria (low loadings and low corrected item–total correlations) to eliminate two items from each one of the factors. The results revealed good reliability and a high correlation between the final scale and similar instruments (such as the Dirty Dozen). As indicated in a previous study [
40], this was the first attempt to validate the SD3 for use among Portuguese-speaking youth and one of the few studies examining dark triad traits among youth under 18 years old.
Although these two previous studies have been the only attempts thus far regarding the adaption of the Short Dark Triad to the adolescent population, they have important limitations that must be considered to generalize their results and the proposed instruments. In the study carried out among Polish adolescents, the item selection process was compromised from the beginning as the study did not start from the complete original scale used in the same way. Additionally, although statistical analyses were carried out to study the structure of the instrument, concurrent validation was performed using general and non-specific dark personality instruments, thus preventing the corroboration of the proposed scale with the measures obtained by other instruments. Regarding the research focused on Portuguese adolescents, the sample was not representative of the adolescent population in general, as its 412 participants were selected from public schools in disadvantaged areas of the Lisbon area, which have distinct characteristics (low status socioeconomic, unfinished education, problems with the law, etc.) that are not representative of the adolescent population. Finally, it should be noted that the authors use non-scaled instruments for the concurrent validation of the proposed scale for the adolescent population, thus limiting the conclusions of the study.
Taken together, these limitations highlight the need to corroborate whether the differences in dark triad traits in the adult population begin during adolescence, which will facilitate a better understanding of the emergence of the phenomenon or how it is expressed in its initial stages. In terms of sex differences, studies indicate that males receive higher scores than females in the analysis of the three dark triad traits in both adults [
18,
41,
42] and adolescents [
40,
43]. Regarding differences in sexual orientation, to date, no investigations have been conducted on adolescents; however, the results for the adult population indicate that bisexual women scored higher than heterosexual women or lesbians on the three traits [
44,
45], while homosexual men scored lower than heterosexual men [
46].
Considering the previous evidence, it is necessary to develop an assessment instrument for analyzing dark triad traits in the adolescent population that enables a rapid estimation of the magnitudes of these constructs. The present study aimed to examine the psychometric properties and factorial structure of the SD3 among Spanish adolescents and propose an adaptation that considers the characteristics of this population and simultaneously allows for the valid and effective measurement of the dark triad traits in minors.
4. Discussion and Conclusions
The reliability analyses of the SD3-A revealed that its adaptation for the Spanish adolescent population provides better results than those obtained using the unmodified scale in Italian adolescents [
37] as well as the version adapted for Polish adolescents [
39]. Furthermore, the proposed scale yielded Cronbach’s Alpha scores—both in the global scale and in the narcissism, psychopathy, and Machiavellianism subscales—that were comparable to those obtained by Jones and Paulhus [
13] regarding the psychometric properties of the SD3 in adults.
The final adaptation of the scale comprising 18 items (SD3-A) is the shortest of all adaptations for the adolescent population thus far [
37,
39]. Moreover, the scale analysis confirmed the trifactorial model of the dark triad personality, which has already been obtained through the application of the SD3 in Spanish adults [
36], Italian adolescents [
37], and Portuguese adolescents in disadvantaged and impoverished zones in the Lisbon area [
40]. These results indicate that the adapted version of the SD3 proposed in this study, the SD3-A, is a valid instrument for estimating dark triad traits in adolescents. Adolescence is a critical stage for the development of personality and dark triad traits [
43]. Furthermore, the association between dark triad traits and behavioral problems in adolescence and adulthood necessitates a rapid and effective instrument for the detection of these traits in adolescents that would facilitate the design and implementation of specific prevention programs. The association of dark triad traits with problematic behaviors such as high-risk sexual behaviors, including coercion [
55], more positive attitudes toward rape [
56], repeated sexual advances [
57], a greater propensity to commit romantic revenge [
58], and greater enjoyment of tormenting others online [
59], as well as both the perpetration and victimization of bullying [
60], justifies the usefulness of similar instruments that can be easily used by all types of professionals.
The descriptive results indicated average values for dark personality traits among the participants, similar to the results of recent studies involving the adolescent population and young adults [
61,
62]. Regarding sex differences, male adolescents had higher levels of dark triad traits than female adolescents, confirming the differences based on gender that have been observed cross-culturally in the adult population [
56,
63,
64]. Regarding sexual orientation, significant differences were observed in Machiavellian and psychopathy, for which adolescents with an exclusively homosexual orientation presented higher scores than their exclusively heterosexual counterparts. Although the differences in narcissism scores based on sexual orientation were not statistically significant, higher scores were observed in exclusively homosexual or bisexual adolescents, which may reflect the beginning of differences in the dark triad traits based on sexual orientation that are observed later in adulthood [
65].
As observed for the adult population [
65], exclusively homosexual male adolescents scored higher in Machiavellianism than their heterosexual and bisexual counterparts, although the differences were not significant, similar to narcissism scores. In contrast to the adult population, a statistically significant increase in psychopathic traits was observed among homosexual male adolescents compared to the rest of the analyzed groups [
65]. The scores obtained based on sexual orientation in female adolescents are more consistent with the results obtained for the adult population to date; according to these results, there is an increase in psychopathic and Machiavellian traits among bisexual women in comparison with exclusively heterosexual women [
41]. The results of this study, which indicate a greater intensity of dark triad traits in exclusively homosexual male adolescents, seem to contradict, at least in this age group, the gender shift hypothesis, indicating that non-heterosexual men have similarities with heterosexual women [
66]. For the adult population, these results can be explained by experiences of discrimination already present during adolescence that manifest as harsher treatment during adulthood [
67,
68], thus activating an adaptive response involving dark triad traits (manipulation, deception, etc.).
Finally, the results observed in female bisexual adolescents, indicating a greater presence of dark triad traits than homosexual and heterosexual adolescents, are consistent with the results in the adult population [
69]. This indicates that the masculinization of behaviors does not occur linearly from heterosexual to homosexual to bisexual women, further demonstrating that some of the more typically masculine traits are more common in bisexual women than in homosexual women [
70]. These results can be considered as a starting point regarding the behavior of the dark triad traits in the adolescent population depending on sex and sexual orientation, requiring further research into whether these differences are motivated by other variables apart from the studied and that have already been considered for the adult population, such as gender roles [
71].
It has been established that younger individuals are less aware of their sexual tendencies and respond more with what is expected of them or because they are afraid of their intimacy being known rather than with the truth. This should be corroborated in further studies, as it can considered a limitation of this study. Another limitation concerns the methodology used. It is necessary to collect qualitative information for the triangulation of the data and greater validity of the results. In-depth interviews may be appropriate given the intimate nature of the data and would help to better understand the reasons for the results presented here.
In this way, possible biases regarding the age of the subjects or their sexual tendencies could be eliminated. However, let us not lose sight of the fact that this is not the aim of this article. As mentioned in the Introduction, we sought to validate a scale in an adolescent population, given the lack of preliminary studies on this subject; therefore, we could not analyze convergent validity. Despite the good psychometric results captured, it is necessary to point out that the results obtained may be due to other factors apart from the dark triad traits, making it necessary that future research verify the scale measure invariance to rule out idiosyncratic use and interpretive bias. The scale adapted to Spanish adolescents (SD3-A) should be applied in subsequent studies using different samples or populations of adolescents to confirm these results. Thus, the proposed tool presented here will gain greater consistency, both internally and externally.