In the 1980s, the so-called Big Five model introduced the notion, in an empirical manner, that all personality traits could be explained by five dimensions and/or factors. It did this by grouping the behavior and conduct of subjects using a lexical approach, and thus allowed the prediction of psychopathology, juvenile delinquency, school and work performance, normality, risk factors linked to physical health and longevity, etc. [
1,
2,
3].
The Big Five Questionnaire (BFQ) is one of the so-called self-reporting types and is based mainly on the NEO-PI and NEO-PI-R questionnaires, but it intends to surpass some matters that were neither clarified nor solved by both these questionnaires; e.g., assigning facets to personal dimensions. As pointed out by Pedrero [
5], the BFQ comes across as being more parsimonious than its predecessors, better matches the main five-factor theoretical principles, and measures a subject’s tendency to distort data and to offer a “distorted” image of oneself, as other personality questionnaires do (EPQ-R, 16 FP, etc.). Another of its characteristics is that it is validated for the Spanish population and offers T-scores in a results table.
In BFQ questionnaires, we find the Big Five Personality Questionnaire (BFQ) for Children and Adults (BFQ-NA) model, which addresses children and adolescents. It is important to remember that different opinions have been expressed on whether adult personality tests are suitable for earlier ages. A general consensus appears to have been reached about the five main dimensions representing stable personality traits in not only adults, but also in children and early adolescents, [
6,
7,
8]. This questionnaire, as pointed out by Ortiz et al. [
9], is derived from the adult questionnaire and is composed of five scales: extraversion—introversion or energy; agreeableness—hostility or pleasantness/cordiality; conscientiousness; neuroticism—emotional stability; and intellect or openness to experience.
1.1. Adolescence: Personality, Emotional Intelligence, and Aggressiveness
A fundamental stage in human development is doubtlessly adolescence. According to Erikson [
10], a search for personal identity takes place in this life stage, which entails difficulties and disagreements with both family and peers. During this process, the self-concept and self-esteem terms become very important; i.e., the image that adolescents have of themselves and how they think that others see them (cognitive aspects [
11,
12],along with the evaluation aspects (affective) that the subject makes of his/her image, which correspond to the emotional part: self-esteem. It can be stated that self-concept comprises physical, academic, personal, and social components [
13,
14]), which give way to differentiation and individualization in relation to others. All of this marks a style of thinking and behavior that leads to being self-assertive in society.
Such differentiation is typical of this life stage, and becoming more independent from the family and personal levels will shape personality in all its cognitive, social, and behavioral aspects [
15]. Authors like Martínez-Otero [
16] state that this stage of uncertainty about the future and the insecurities that adolescents experience, which are connected with this permanent process of searching for and redefining their identity, can even decrease their mental health.
With all these difficulties and circumstances, in this development stage, to the already known controversies with the family, we can add another series of factors (food, health, etc.) that lead youths to have serious problems as they mature as human beings. Of all these problems, one particularly stands out: youth violence. Adolescents’ aggressive conduct has systematically increased in our society [
17,
18,
19]. This is the reason for why today’s studies of adolescence examine aggressiveness in youths in academic, social, and family settings. Some papers have related aggressiveness in adolescents with personality, and those by Carraco and Del Barrio [
20] particularly stand out in this respect. These authors have demonstrated that many factors exist in aggressiveness that can be divided into two large groups: social factors, where solutions are of the political kind, and personal factors, where interventions are mainly of the psychological kind. These authors start with the notion that if the personality factors that predict aggressive conduct can be isolated, a relevant step toward preventing such conduct will have been taken. Like the above-cited authors, in our study, we began with the Big Five Personality Model, which is similar to the Three-Factor model by Eysenck [
21] and maintains that aggressiveness correlates with different personality factors. Indeed, neuroticism comes across as a factor that multiplies the risk of aggressiveness due to the lack of control and empowered impulsiveness. Apart from personality, another series of factors can be found that influence the appearance of aggressive conduct.
On the one hand, the concept of emotional intelligence (EI) is very broad, and many definitions have been used in the past. In our study, we used the definition provided by Salovey and Mayer [
22]: EI can be defined as a subject’s ability to regulate his or her own and other people’s emotions and/or feelings, and that serves to guide both our thinking and our actions. The way in which EI is measured is also an important consideration. Two main schools of thought exist: one that defines EI as an emotion-related skill, similar to cognitive abilities [
23,
24] and another one defining EI as a set of emotion-related traits more akin to personality [
25]. The latter [
26] is evaluated with an instrument comprising short verbal statements, which is called the “Index of perceived or self-reported emotional intelligence”. Within these questionnaires on perceived EI are the Trait Meta-Mood Scale (TMMS; [
23]—adapted to Spanish by Fernández-Berrocal et al.[
27]—which is the scale used in this study, as well as Schutte’s lE scale [
28].
Emotional intelligence (EI) has been systematically and thoroughly studied in the last few decades in relation to youths. It is worth mentioning the studies by Berrocal and Aranda [
29], who reviewed works in academic contexts, that by Buenrostro-Guerrero et al. [
30] about the relation between EI and academic performance, that by Rodríguez [
31] on intervention programs for EI in youths with Down’s syndrome, or that by Martín and Gonzalez [
32] about youths’ physical activity with EI programs. Other research works can be found about the use of mobile phones, youths with autism spectrum disorder, and/or parental styles. However, fewer studies refer to the relation with aggressiveness. However, the study by Palomera, Salguero, and Ruiz-Aranda [
33], which was conducted with secondary education students, stands out, as its results show how the skill of perceiving emotions is a stable predictor of less clinical and emotional maladjustment and of greater personal adjustment. We particularly highlight the work by Saura et al. [
34], who analyzed aggressive behavior in adolescents in relation to EI. Their results indicated that adolescents with high scores in aggressive physical and verbal behavior, hostility, and anger obtained significantly lower scores for the EI trait than their peers with low scores for aggressive physical and verbal behavior, hostility, and anger. Other studies, like that by Garaigordobil and Oñederra [
35], have demonstrated that subjects who had been victims of bullying and youths who scored high in antisocial conduct obtained low EI scores.
All these studies relate aggressiveness with EI, while others have also related personality with EI. Authors like Ciarrochi, Chan, and Caputi [
36] investigated EI in relation to a series of criterion variables. Their study verified how EI related positively with some personality variables like empathy, self-esteem, extraversion, and openness to feelings. The trait models considered EI to be a series of stable personality traits, socioemotional competence, motivational aspects, and different cognitive skills [
37]. In Spain, this has been the most successful working model in organizations until quite recently, due mainly to the impact of Goleman’s book [
38,
39]