The dark triad (Machiavellianism, psychopathy, and narcissism; Paulhus and Williams, 2002) depicts a constellation of subclinical and malevolent personality traits, sharing a common core in terms of antisocial and aversive behaviors, including a tendency to deceive, manipulate, and exploit others (Paulhus and Williams, 2002). Machiavellianism lays on cynical behaviors and the inability to recognize the emotions of others (Láng and Birkás, 2014). In turn, psychopathy relies on callous affect, erratic lifestyle, and antisocial behavior (Neumann et al., 2007), whereas narcissism incorporates a blend of vanity, egocentric admiration, and a desire for superiority that negatively impacts social relationships (Kauten and Barry, 2016). Overall, adolescents with high dark triad tend to be antisocial, vulgar, and academically disengaged (Zhang et al., 2015). Specifically, adolescents with high Machiavellianism show emotional problems such as lack of sympathy (Sutton and Keogh, 2000) and behavioral problems (Zhu et al., 2021), including aggression, a higher tendency toward antisocial practices, lower altruistic concerns (Swami et al., 2010), and equity sensitivity (Woodley and Allen, 2014). Psychopathy is also negatively related to prosocial practices (Papageorgiou et al., 2020) and different social skills such as communication, group collaboration (Anwar and Zubair, 2021), altruistic prosociality (White, 2014), and equity sensitivity (Woodley and Allen, 2014). Regarding narcissism, research emphasized a positive association (Papageorgiou et al., 2020), revealing that to increase the admiration of others, narcissists intentionally distort the memory of events to increment their self-esteem (Hart et al., 2018), and, in turn, accommodate their grandiose image as altruistic people (Palmer and Tackett, 2018). However, some studies revealed that this trait was positively related to antisocial and aggressive behaviors and, thus, negatively associated with prosociality: through aggressive behaviors, narcissists can dominate over peers and reinforce their grandiose self-image (Fanti and Henrich, 2015). Notably, narcissism was also found uncorrelated to prosocial behavior, such as equity sensitivity (Woodley and Allen, 2014).

Trait Emotional Intelligence involves a constellation of emotion-related dispositions, which lay at the lower levels of personality hierarchies (Petrides and Furnham, 2001; Petrides et al., 2007). Research about the relationships between the dark triad and TEI in adolescents is extremely scarce. Zhang et al. (2015) revealed that adolescents (13–19 years old) with higher levels of Machiavellianism and psychopathy showed lower levels of TEI, whereas adolescents with higher levels of narcissism demonstrated higher levels of TEI. Studies on adults showed that both psychopathy (Petrides et al., 2011; Jauk et al., 2016) and Machiavellianism (Austin et al., 2014) were negatively related to TEI (Miao et al., 2019), although Machiavellianism was also found positively related to higher levels of TEI in men (Jauk et al., 2016) and the perspective-taking facet of cognitive empathy (Szabó and Bereczkei, 2017). The positive Machiavellianism-TEI association can rely on emotional competence as a necessary means for manipulative behavior (Jauk et al., 2016). Yet, a meta-analytic review of Miao et al. (2019) showed that narcissism and TEI are unrelated, since some studies showed positive correlations between narcissism and the different facets of TEI (Petrides et al., 2011; Szabó and Bereczkei, 2017), including assertiveness (Watson et al., 1988), optimism (Farwell and Wohlwend-Lloyd, 1998), positive social relationships (Foster and Campbell, 2005), whereas others showed negative relationships, as narcissists showed lower levels of empathic concern (Watson and Biderman, 1994). These contradictory results can be in part due to the double facet of narcissism, involving grandiosity (high self-esteem, interpersonal dominance, and tendency to overestimate one’s capabilities), or vulnerability (defensive, avoidant, insecure, hypersensitive, and vigilant for criticism) (Miller et al., 2011). Thus, grandiosity would be positively related to TEI, whereas vulnerability would be negatively related (Zajenkowski et al., 2018).

Adolescence marks the development of more efficient forms of prosocial behaviors persisting into adulthood (Eisenberg et al., 2005). Adolescents’ development depends on both social contexts and personality characteristics such as TEI (Gallitto and Leth-Steensen, 2019). Emotional and social competencies underpinned by TEI (e.g., emotionality and sociability) are crucial in acting prosocially (Petrides et al., 2006). Managing emotions allows people to elaborate their own perception of people’s feelings into motivation to help and collaborate with others (Zhao et al., 2020). Petrides et al. (2006) found that higher TEI scores were related to more nominations from children for being cooperative, kind, and having leadership qualities and fewer nominations for being a bully. In addition, TEI was positively correlated with social competencies and kindness. Mavroveli et al. (2007) confirmed that adolescents with higher TEI scores were more likely to be nominated as cooperative by their classmates, whereas Mavroveli and Sánchez-Ruiz (2011) showed that higher TEI was associated with higher peer-ratings for prosocial and fewer nominations for antisocial behaviors. In addition, youth emotional and sociability competencies underpinned caring and connections with others positively predicted social sustainability both in terms of altruism and equity (Giancola et al., 2021).

Based on personality approach on prosociality (e.g., Oda and Matsumoto-Oda, 2022), describing personality as one of the main contributors to people’s disposition to act prosocially and the feeling-oriented approach (e.g., Cialdini et al., 1987), stating that prosocial practices mainly rely on emotional regulation and positive emotional experiences, this study detected the mediating effect of TEI on the association between the dark triad and prosocial sustainability declined in terms of altruism and equity.

Hypotheses were formulated as follows:

A total of 129 healthy late adolescents (85 women; M_age = 19.96 years; SD_age = 1.05; range_age = 18–22 years) participated in the study. This study used a cross-sectional web-based survey design, and data were collected in September and October 2021. Using an online link distributed via different social media platforms, all participants were requested to electronically sign the informed consent, and complete the self-report measures and a short demographic questionnaire. Given the cross-sectional-based survey design, participants were selected from different regions of Italy, mostly from Abruzzo. The internal review board approved the study.

The Dark Triad Dirty Dozen (Schimmenti et al., 2019) assesses Machiavellianism (e.g., I tend to manipulate others to get my way), psychoticism (e.g., I tend to be unconcerned with the morality of my actions), and narcissism (e.g., I tend to seek prestige or status). It consists of 12 items along a 5-point Likert-type scale (0, not at all; 4, very much). Cronbach’s α was 0.64 for psychopathy, 0.77 for Machiavellianism, and 0.82 for narcissism.

The Trait Emotional Intelligence Questionnaire—Short Version (TEIQue—SF; Di Fabio and Palazzeschi, 2011) evaluates TEI. The questionnaire was formed by 30 items along a 7-point Likert-type scale (1, completely disagree; 7, completely disagree) (e.g., Expressing my emotions with words is not a problem for me). In this study, the global TEI score was used and Cronbach’s α was 0.85.

The Altruistic Actions Scale (Corral-Verdugo et al., 2015) evaluates altruism as behaviors directed at helping others (e.g., visiting sick people and giving money to poor people). It consists of 10 items along a 4-point Likert-type scale (0, never; 3, always engage in such an action) (e.g., “Provides some money to homeless”). Cronbach’s α was 0.80.

The Equity Scale (Corral-Verdugo et al., 2015) taps behaviors directed at setting equal opportunities and treating conditions, regardless of gender and economic status. The scale is formed by seven items along a 5-point Likert-type scale (0, totally disagree; 4, totally agree) (e.g., “Girls and boys have the same educational opportunities”). Cronbach’s α was 0.61.

This study has at least two limitations worth noting. First, the researchers used a web-based survey design; thus, further studies should include performance tasks for measuring altruism and equity. Second, the dark triad was evaluated by a concise measure that did not highlight subfactors, such as primary and secondary psychoticism or grandiose and vulnerable narcissism. Thus, future research should consider more specific subdimensions of the dark triad to evaluate their differential effects on prosociality and TEI.