Technologies have radically disrupted the lives of people of all ages, but especially those of young people and adolescents. The media and communication ecosystem has changed [
1] and it has gone from the hegemonic model of the mass media to another model of production and dissemination of information, which is characterized by a great variety of personalized communication processes which are more horizontal, where the users decide what is worth disseminating and what is not [
2]. Education has also been influenced by this model and has incorporated the development of media competence, which is based on digital competence. This includes going beyond the knowledge of the environment; that is, moving towards the development of new knowledge, skills and attitudes that enable social transformation [
3,
4,
5], promoting the responsible use of technology within people’s daily activities [
6,
7,
8].
Mobile telephones are one of the technological tools that have a very important impact on the educational field, inside and outside the classroom, and that are useful for both students and teachers of all educational stages. What in previous years many internal regulations of the schools prohibited, has become today one of the most useful objects as it helps the student to engage interactively, learn and get closer to reality.
Lately experts have focused research on mobile learning. They have analyzed and explained how mobile devices allow students to access learning resources at any time and place, and have also examined their use by teachers in teaching and interactive tutoring [
10,
11]. However, although mobile phones have multiple benefits, especially in the educational field, specifically, in the learning outcomes [
12,
13,
14], in the construction of knowledge [
15], and in the increase of the students’ motivation and commitment [
16], their excessive use can have negative consequences in children and adolescents, both personally and in their family, academic and social life [
17]. This use can also be harmful to people’s health, as it can cause headaches, fatigue, concentration problems, insomnia, and visual and hearing problems [
18,
19,
20]. Likewise, other authors, such as Enez et al. [
21], have identified, in young people addicted to mobile phones, problems in some dimensions of personality, such as low self-esteem, introversion and loneliness.
1.1. Research on Mobile Addiction
The mobile phone has proliferated in recent decades due to the countless advantages it offers, such as portability and Internet surfing, as well as access to social networks, navigation systems, real time information broadcasting, cameras, and multimedia players. In Spain, according to a report by Epdata [
22], 90% of adolescents, whose ages fluctuate between 10 and 14 years, already have a smartphone. Of these, 40% of male adolescents affirm that they consult their mobile phones between 50 to 100 times a day, which means that they have active contact with their smartphone every 15 or 20 min, and 6% indicate that they touch the mobile about 450 times a day, which implies active contact with the device every 3 min. For their part, 45% of women of the same age affirm that they consult their mobile phones 50 times a day, which means looking at it every half hour, and 4% of them consult their mobile phones more than 450 times a day [
23]. Although there is a growing interest in investigating the influence and consequences of this excessive use in children and adolescents, its effects vary, and the real magnitude of its impact remains unclear [
24].
The first investigations that raised the alarm about mobile addiction in Spain go back to the studies of Muñoz-Rivas and Agustín [
25]. These authors stated that the main risk group are young people. Subsequently, there was a greater interest in investigating the symptoms and characteristics of this addiction. Subjects with this type of compulsive behavior [
26] present a state of wakefulness or permanent alert towards any signal that comes from their mobile phone, which causes the uncontrolled or compulsive need to consult it constantly and anywhere [
27]. All in all, this cyber addiction, which does not involve the consumption of any substance but is a behavioral addiction, is characterized mainly by a pattern of problematic use, dependence, and lack of control [
28,
29,
30,
31,
32,
33]. Goswami and Singh [
34] point out 7 criteria for identifying mobile phone addiction: tolerance level, abstinence, non-specific use, difficulty of control, excessive time of use, interference with other activities, and continued use.
In the empirical research on the consequences of the mobile phone use in recent years, the effects observed are not homogeneous. Some argue that they have positive effects, others negative, and even a zero effect is noted [
35,
36]. Despite the variety of opinions and findings, a number of studies conclude that there is a negative relationship between mobile dependence and academic performance in both high school students [
37,
38,
39] and college students [
40,
41,
42,
43,
44]. Along these lines, Gi et al. [
17] found that dependence on smart phones negatively predicted student performance in language and math. From another perspective, Beland and Murphy [
45] investigated the impact of schools banning mobile phones on student test scores and found that the ban improved the results of low-performing students. Bhatt et al. [
46], Han et al. [
47], and Lee et al. [
48] have shown that excessive mobile phone use can adversely affect the mental health and well-being of young people.
In a Spanish research study on Internet and mobile phone use among young people, Ruiz, Sánchez and Trujillo (2016) [
49] found that 39.5% of them had problems with mobile phone dependency. The authors conclude that it is fundamental to empower the role of families and educational centers to provide young people with strategies that allow them to use mobile phones in a balanced way. In relation to sex and age, according to De la Villa-Moral and Suárez [
50], girls and older adolescents suffer more problems related to mobile phone use.
In short, the growing interest in research on the impact of mobile phone addiction on young people is notorious [
51], but its relationship with other important elements of education such as education in values has been minimally studied. This is evidenced by the scarce specific literature that exists today. One of the few studies is that conducted by Son and Huang [
52], who analyze how mobile phone use influences the values of university students in a sample of 469 participants. Researchers have found significant differences in the values of equality and respect for parents and elders, and a negative correlation with students’ values of social justice and cleanliness. Consequently, they conclude that dependence on mobile phones has a significant impact on the values of university students.
1.2. Sustainable Education, Education in Values and the Use of the Mobile Phone
Despite achievements in health and education, more than one billion people, many of them in conflict-affected areas, did not benefit from the Millennium Development Goals (MDGs). Therefore, Agenda 2030 has been proposed as a second principle so as to not leave anyone behind [
53].
SDG 4, one of the 17 goals that make up the UN Agenda 2030 for Sustainable Development [
54], aims to ensure access to quality education at all levels and to promote lifelong learning opportunities for all, and emphasizes special attention to the most disadvantaged social sectors, such as women in the most vulnerable communities. From the seven goals and the three implementation methods which comprise it, four of them are related to the objectives of our study: making sure that all children finish primary and secondary education, which must be fair and of quality, and creating the corresponding and effective learning results (4.1), that children have a quality early stage education, so that they are ready for primary education (4.2), guaranteeing fair access to quality training (4.3), and also focusing their attention on the importance of education for sustainability (4.7). As part of this last objective, we must remark on the importance of the students acquiring theoretical–practical knowledge required in order to promote sustainable development and adopt sustainable lifestyles.
Quality education goes beyond literacy rates, tuition fees, number of schooled children, student–teacher ratio or even the rate of students who have achieved reading, writing, and arithmetic competences. According to UNESCO [
55], education must be based on the development of the three main commands: cognitive (knowledge and thinking tools to understand the SDGs), socioemotional (social skills to collaborate, negotiate, communicate, values, and self-reflection), and behavioral (action capability, active compromise with citizens). However, SDG 4 and its goals mainly focus on the first command, having identified some weaknesses in the training of attitudes and values [
56].
A second existing problem is the persistence of gaps in the achievement of the SDG 4 goals [
57]. Thus, the lowest rates of reading and mathematical competences are found in Sub-Saharan Africa, where 88% of the children in primary and secondary education do not have a command in reading and 84% of them do not have a command in mathematics. Likewise, there is a disparity in the participation of children in early stage education; in developed countries children are almost 100% present in early stage education, whereas in developing countries only 43% are present. Furthermore, the progress of children attending school, especially of girls, has come to a standstill in Central Asia, Northern Asia, West Asia, and Sub-Saharan Africa. In Central Asia, 27% more girls than boys of schooling age do not attend primary school. Additionally, more than half the schools in Sub-Saharan Africa lack the basic elements for a quality education: qualified teachers, basic services of drinking water, the Internet, and computers. This situation worsens even more if we consider that the official reports about the Sustainable Development Goals, such as the UN Report [
58], do not include progress in other main elements related to comprehensive training and sustainable development, such as socioemotional command, values, or ethics training.
Quality education (SDG 4), which is what in pedagogy is known as integral education [
59,
60], is not only a right, but also the basis and strategy for social, economic, and environmental development with guarantees of current and future sustainability of all populations [
61,
62]. According to the terminology of the SDGs, this educational approach is known as Education for Sustainable Development (hereinafter ESD) [
63]. It is characterized as such because it goes beyond the simple transmission of knowledge, as it promotes the acquisition of competences such as critical thinking, values that people need to have a successful life, to make informed decisions, and to take an active role both at the local and global level [
59]. The purpose of ESD is for students to acquire the theoretical and practical knowledge necessary for the adoption of sustainable lifestyles, based on human rights, gender equality, solidarity, responsibility, the promotion of a culture of peace and non-violence, and the positive valuation of cultural diversity. In sum, ESD should be understood as an education that contributes to the construction of culture in and for sustainable development. As Irina Bokova, former Director General of UNESCO [
55] points out: “A fundamental change is needed in the way we think about the role of education in global development because it has a catalytic effect on the well-being of individuals and the future of our planet. Now more than ever, education has a responsibility to keep up with the challenges and aspirations of the 21st century and to promote the right kinds of values and skills that will lead to sustainable and inclusive growth and a peaceful life together (p. 7).”
On the contrary, education that exclusively promotes economic growth leads to an increase in unsustainable consumption patterns [
64]. Therefore, it is necessary to empower students so that they are able to reflect on their own actions, make conscious decisions and act responsibly for the sake of environmental integrity, economic viability, and a more sustainable and just society for all.
Societies in the world struggle to keep up with technological progress and globalization and in this process they face new challenges such as greater complexity and uncertainty, greater individualization, degradation of ecosystem services, greater vulnerability and exposure to natural and technological disasters, and expansion of economic and cultural uniformity. This reality requires a creative and autonomous action of “sustainable citizens” [
65,
66], who are capable of knowing and understanding the complex world in which they live, and who can collaborate and develop actions for the sake of a positive change. To implement these actions, “sustainable citizens” need to display five types of competences that include cognitive elements but, especially, affective, volitional, and motivational elements (values, positive attitudes, and affective disposition): rule-based competence, collaboration, critical thinking, self-consciousness, and digital thinking [
64]. These competences must include subject teaching [
65] promoting experiential learning, initiative, the active participation of children and adolescents [
66,
67], and critical thinking [
68,
69]. They are necessary for all students of all ages and can be understood as key, transversal, and multifunctional competences [
70,
71,
72] as they allow solving the obstacles that arise on a daily basis [
73]. De Haan [
74] and Rieckmann [
75] argue that these competences are related to socioemotional learning objectives and are crucial to achieve sustainable development. Based on this, we propose specific values and attitudes for each of the five key competences (
Table 1).
Based on this framework, this study aims to analyze and identify possible relationships between the values taught in school and addictions to mobile phones. Along these lines, the proposed hypotheses are the following:
Hypothesis 1 (H1). There is a negative and statistically significant relationship between the teaching of values in schools and addiction in children and adolescents.
Hypothesis 2 (H2). The teaching of values in schools is a predictor of the decrease and/or mitigation of mobile addiction.