The repercussion of the variables that form the dark triad has an enormous relevance in the field of education. These variables have been studied in isolation for decades. For example, Sidis (1911) already studied psychopathy in relation to anxiety and fear; Emerson (1916), on the other hand, studied how narcissism along with sublimation and self-eroticism helped to capture character both individually and socially. On the other hand, the work of Maritain (1942), "The end of Machiavellianism" is well known. However, it is not until the study of Paulhus and Williams (2002) that the interrelation of three higher-order personality constructs was established.  They called it the Dark Triad of personality, composed of Machiavellianism, narcissism and psychopathy. Shortly after the finding of Paulhus and Williams (2002), Lee and Ashton (2005) established that the model of the Dark Triad correlates negatively with the "Big Five" and "Hexaco" models.

Several years later, Jones and Paulhus (2009) found the common points between these three types of personalities, arguing that "subjects with these traits share a tendency to be insensitive, selfish and malicious in their interpersonal relationships" (p.100).

It is necessary to identify and intervene as effectively as possible in the subjects who possess these personalities, and in those who must face this task. In this sense, González (2015) affirms that "the behaviors presented by individuals with features of the Triad have been culturally cataloged as undesirable for the development of life in society" (p 256).

Recently, Muris et al. (2017) have carried out a meta-analysis about the literature generated by the Dark Triad. Among its objectives, one of them was to evaluate the interrelations between narcissism, Machiavellianism and psychopathy; the gender differences in each trait; how these traits are related to "normal" personality factors; and the psychosocial correlates of the Dark Triad. Regarding their first objective, as in previous studies, they found inter-correlations between the different traits that make up the Dark Triad. They found likewise that there were no significant differences or whose effect size was very small (r = .15 and r = .16) in terms of gender in the traits of Narcissism and Machiavellianism, however, with respect to Psychopathy, they observed a greater link with the masculine gender (r = .29, which decreases to r = .24 by controlling the variance shared between the different traits). Regarding the third objective, they observed similar results to those of Lee and Ashton (2005) or Jakobwitz and Egan (2006). According to this study, the Dark Triad is related to the kindness factor of the Big Five and with the honesty-humility factor of Hexaco. Finally, they identify 102 studies that include 122 samples with a total of 46234 participants in which 180 psychosocial correlates are examined, and even considering the benefits that the Dark Triad can bring to those who score high in it, the general view is that narcissism, Machiavellianism and Psychopathy represent the malevolent side of human nature and therefore are inherently maladaptive. Thus, it could be said that all the traits of the Dark Triad are accompanied by negative psychosocial consequences.

The instrument was translated from the reduced version of the dark triad (SD3) of Jones and Paulhus (2014). In order to normalize the sample, the outliers detected by SPSS V23 were eliminated first. Thus, the sample of 250 people finally included 217 participants, of whom 179 (82'48%) were women and 38 (17' 51%) men with an average age of 20'47 and a standard deviation of 2'8. In the exploratory analysis, we proceeded with the SPSS 22.0 to calculate the descriptive statistics of the sample, analyzing also the properties of the items. It was found that the univariate and multivariate normality of the distribution showed adequate parameters (Byrne, 2012, González, Abad and Lévy, 2006, Kline, 2011). Then, the exploratory factorial analysis was carried out using the FACTOR programme (Lorenzo-Seva and Ferrando, 2006), using PA-MBS as a procedure to determine the number of factors, MRFA as a method of extracting factors and Promin as a method of rotation. Next, the reliability of each of the dimensions was obtained by the Cronbach alpha coefficient. Results In the first place and through the exploratory factorial analysis, it was verified, with respect to the structure, that the 3-factor model showed adequate values. The saturation of 25 of the 27 items in their theoretical factors far exceeded the threshold of, 30. Likewise, the indices of discrimination of the items (by means of correlation item-total corrected, obtained with ViSta-CITA) and the estimated reliability of the factors were found to be of a sufficient size. On the other hand, the correlation between factors (none reaches .7) allows us to anticipate that the factorial structure does not coincide with the original, but it is adequate. In this way, the inventory was provisionally constituted by three factors of 12, 6 and 7 items respectively. In short and to confirm the adequacy of the model with 3 factors, we proceeded to calculate the statistics corresponding to the exploratory analysis, yielding favorable results in the explained variance, index of discrimination of the items, estimated reliability of the factors and of the whole test, the root of the average quadratic residual, average of the residuals and their variance. Although the total variance explained by the factorial techniques is 49.49%, the reliability of each factor was high: .825 in factor 1; .729 in factor 2 and .763 in factor 3; the reliability of the whole questionnaire is raised to .81.

The Dark Triad questionnaires (SD3-27 and DDDT-12) are instruments which are being currently used more and more in different Spanish investigations (Pozueco, 2015). Although, in view of these results, it seems possible to use the instrument translated from the reduced version of the dark triad (SD3) of Jones and Paulhus (2014), it is also possible to expand the number of items in order to balance the weight of each factor in the instrument as a whole. That is to say, the reliability is similar to that obtained by the instrument in its English version, nevertheless the factor-items structure has been modified and its revision is recommended to ensure the correct agreement of factors and constructs.

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