The present article aims to shed light on exploring the issue of bullying in preschool children, with a special focus on early forms of anti-social and aggressive behaviour and suggestions about the role of the school, based on the presentation of prevention and intervention programmes in preschool education settings. The most typical forms of bullying in preschool education settings are physical aggressiveness, social exclusion and rumor spreading. Most studies indicate that physical aggressiveness is prevalent in boys, while relational and verbal aggressiveness is prevalent in girls. The role of preschool educators is crucial, as they need to learn to identify and manage early forms of aggressiveness. Therefore, their training is imperative, as they need to carefully evaluate each incident, while creating a positive learning environment and applying strategies for bullying prevention and intervention.

Goal achievement is considered to be related to need satisfaction, motivation, and self-esteem. The self-assessed abilities for goal achievement were operationalized as positive self-talk, perceived self-efficacy, the performance level of doing a task, the aspiration level, the in/congruence between performance and prognosis, and frustration tolerance to pursue one’s goals in spite of some obstacles. In total, 392 students whose mean age was 21 years old were investigated, divided in sub-samples, with the positive self-talk scale from the ASTQS questionnaire, the self-efficacy scale by Schwarzer & Jerusalem, and the AHA computerized test method from Vienna test system. Students’ self-assessment of one’s abilities for goal achievement revealed the most frequent high levels of perceived self-efficacy and good performance in coding tasks. The other self-assessed abilities for goal achievement were expressed more often at a medium level. The gender differences in the performance level of doing a task were compared to some previous results that indicated a variety of trends, because of the age peculiarities and the types of the tasks that were executed. The advance in age was related to more frequent use of positive self-talk and lower aspiration level, besides to lower performance level. The proposed model of the abilities for goal achievement was successfully approbated in this study revealing the strengths in the students’ self-assessment of one’s abilities for goal achievement and some weaknesses that should be the focus of further interventions in order to increase the students’ frustration tolerance ability and the use of positive self-talk. Keywords: aspiration level, frustration tolerance, life goal, perceived self-efficacy, positive self-talk.

Literature ReviewAggression can be described as an ensemble of mechanisms formed during the course of evolution in order to assert oneself, relatives or friends against others, to gain or to defend resources by harmful damaging means. These mechanisms are usually stimulated by feelings like stress, anger, frustration and fear or pleasure. Causes of aggression and aggressiveness can be biological, psychological and sociological [1]. Self-esteem is a significant psychological factor in everyday life. It can be defined as a pervasive force in human motivation that is generally adaptive and associated with a broad range of desirable outcomes. Self-esteem is characterized as a complex concept by various theories and a series of distinctions [2]. According to the researchers, the relation between self-esteem and aggression is controversial [3], as both low and high self-esteem have been associated with antisocial and aggressive behaviour [4]. Research shows the complexity of the relation between aggression and selfesteem and reflects the aforementioned theoretical controversies. In Greece, there is paucity of research on self-esteem and the relation between self-esteem and aggression, especially in adolescence. Papanis and Triantos [5] concluded that adolescent population was rather heterogeneous and that there were some differences in self-esteem with respect to age and gender. Boys were found to have higher self-esteem than girls, although it was also found that both boys' and girls' self-esteem was lower than adult's self-esteem. MethodologyThe aim of the paper is to represent the characteristics of self-assessment in children who are prone to aggression in school and to examine if students with high self-esteem are more or less prone to aggression. An additional aim is to explore the role of family structure in adolescents' self-esteem and engagement in aggression and the impact of gender in aggressive behaviours. The sample of the study is consisted of 124 high-school students living in Athens, in the capital of Greece. For the collection of the data, a questionnaire comprising valid and reliable scales is used. Statistical analysis of the survey data is performed using the IBM SPSS Version 22 software for Windows. Both descriptive and inferential statistical analysis are performed. Pearson's r correlation coefficient [6] and the independent samples T-test [7] are used.