Gender and Age Differences in Self-Reported Aggression of High School Students

Abstract

The purpose of the study was to (a) investigate gender and age differences in physical aggression, verbal aggression, anger, and hostility, and (b) examine the discriminatory power of the Greek version of the Aggression Questionnaire (GAQ) with high school students. The sample of the study consisted of 658 high school students (321 boys and 337 girls), with an age range from 13 to 17 years (M = 15.3, SD = 1.5). The students completed the Aggression Questionnaire adapted to Greek. Regarding gender, the overall correct identification rate in the discriminant analysis showed that 73.3% of the cases were correctly classified. In addition, the results indicated that physical aggression declined with age and that, compared to boys, girls of higher grades apply more indirect forms of aggression, such as anger and hostility. The findings of the study provide important information regarding the expression of aggressive behavior during adolescence.

Keywords

aggression discriminant analysis gender differences

In the past 20 years an increase of violence and aggressive acts in the school context, mainly among schoolmates, has been reported (Olweus, 1993; Rigby & Slee, 1991; Smith & Sharp, 1994; Swearer, Espelage, Vaillancourt, & Hymel, 2010). Furthermore, research findings and reports led Johnson (1999) to point out that violence and aggression in the U.S. schools is a problem that needs to be addressed. Findings from Germany evidenced that the frequency of aggressive acts is getting higher; however, the impact of these behaviors on both schoolchildren and teachers has not been determined yet (Bründel, 1995). In a similar vein, Tsorbatzoudis (2005) provided evidence that Greek school directors perceived an increment of student aggressive acts during school courses in a period of 4 years. Moreover, a number of studies indicated that Greek students are involved in different forms of aggressive behavior such as bullying (Giovazolias, Kourkoutas, Mitsopoulou, & Georgiadi, 2010; Sapouna, 2008) and physical aggression (Tsorbatzoudis, 2006).

There are many perspectives on the study of human aggression, such as biophysiological, social-psychological, learning-oriented approaches, and multidimensional models. The learning-oriented approaches and the multidimensional models have dominated the study of aggression in educational settings (see Bandura, 1973; Baron & Richardson, 1994; Eron, Walter, & Lefkowitz, 1971; Huesmann, 1988; Sapouna, 2010; Siegman, 1994; Siegler, 1994).

According to learning-oriented and multidimensional perspectives, several occasions in everyday life at school or home and during social interaction have been identified to initiate and link aggressive behaviors. For example, there are reports that aggressive children are more likely to come from families where the child-rearing practices are authoritarian in nature and they are characterized by harshness and punitiveness (for a reviews, see Reker, 2010; Smith & Myron-Wilson, 1998). These children also show poor socialization as they tend to be rejected by peers, lack friends, and feel lonely at school (Boulton & Smith, 1994; Rigby & Slee, 1993). Children and adolescents who have been physically abused show lower social effectiveness with peers and higher levels of aggression in the school setting (Rogosch, Cicchetti, & Abner, 1995). Moreover, there is evidence suggesting that hostile adolescents report low levels of social support and display high levels of social conflict (Scherwitz, Perkins, Chesney, & Hughes, 1991).

Gender and age have been identified among the variables that affect the initiation and expression of aggressive acts. Regarding gender, findings from the general population indicated that males both instigate and receive more physical aggression than females do (Archer, 2009; Eagly & Steffen, 1986; Frodi, Macaulay, & Thome, 1977). There are also some reports suggesting that this is true irrespective of age; males engage more in aggressive acts both as actors and as victims than females do (Austin & Joseph, 1996; Hodges & Perry, 1999).

Research findings in educational settings failed to give a clear picture. For example, Talbott (1997) reported that at the age of 11, girls and boys report similar incidence rates of physical aggression. Finkelstein, Von Eye, and Preece (1994) also found no gender differences in physical aggression and verbal aggression in school students in the age group of 13 to 15 years. In addition, Andreou (2000) showed that there were no gender differences concerning the expression of somatic and psychological aggression in 8- to 12-year-old school children. Contrary to these findings, Bjorkvist, Lagerspetz, and Kaukianen (1992), who applied a stepwise discriminant analysis of items on their aggression measure, reported differences between males and females in the form of aggression. Indirect aggression (e.g., backbiting, spreading vicious rumors) was more typical of females, while physical aggression items (e.g., tripping, kicking) was more typical of males. In another study addressing gender and age differences, Owens and MacMullin (1995) reported that Grade 9 girls (age 14) were rated by their peers as using more verbal aggression (e.g., yelling, name calling) than Grade 11 girls. In addition, Grade 11 girls were rated by their peers as using more indirect aggression (e.g., gossiping, ignoring) than Grade 6 girls. Finally, indirect aggression was higher for girls than for boys in Grades 9 and 11.

Buss and Perry’s Aggression Questionnaire has assisted in the advancement of research in aggressiveness. This questionnaire measures four subtraits representing different components of aggression, namely, physical aggression, verbal aggression, anger, and hostility. Results from a number of studies (Archer, 2004; Harris, 1995a, 1997; Morren & Meesters, 2002; O’Connor, Archer, & Wu, 2001; von Collani & Werner, 2005) confirmed that male students reported being more physically aggressive and somewhat more verbally aggressive than females. A small gender difference in the same direction was also detected for hostility but not for anger (Buss & Perry, 1992).

Other researchers indicated that assault rates and arrest rates for aggravated assaults peak in the age range of 20 to 24 years and decline progressively thereafter (Campbell, 1995; Lore & Schultz, 1993). However, using the Aggression Questionnaire, Harris (1996) examined older students of both genders and found that males reported higher physical aggression and verbal aggression than females. She also suggested that as people get older, their level of aggressiveness drops. Harris and Knight-Bohnhoff (1996) reported that toward the end of adolescence less aggressiveness was observed in both genders, suggesting that aggressiveness changes over the course of one’s life.

As it is apparent from the review of the literature so far, there is no clear evidence concerning the interactive effect of age and gender on the expression of aggressiveness in the school context. This effect is of particular interest, since there are findings that the meaning of male and female aggressiveness varies across different age groups. Educational psychologists and school teachers would benefit if they develop an awareness of the pattern of aggression across gender and age, so that more effective intervention programs dealing with aggressive acts in school could be designed. Thus, the main objective of the present study was to investigate gender and age differences in physical aggression, verbal aggression, anger, and hostility. Based on previous research, it was expected that male participants would report more direct forms, such as physical aggression and verbal aggression, whereas females would report more indirect forms, such as anger and hostility.

A secondary purpose of the study was to examine the discriminatory power of the Greek version of the Aggression Questionnaire (GAQ) with high school students (Meyers, Gamst, & Guarino, 2006). Todd and Bradley (1994) suggested that the ability of items or scales to discriminate between specific groups is of highest priority in the instrument development process. Thus, for the assessment and treatment of aggression, it is essential to expand the validity indices by examining the discriminatory power of the Aggression Questionnaire.

Method

Participants and Procedure

Participants were 658 high school students (321 boys and 337 girls). Students’ age ranged from 13 to 17 years (M = 15.3, SD = 1.51). Stratified selection of the sample was used. Six out of the 12 educational administrative regions of Greece were randomly selected. One public high school was randomly selected from each capital city of each selected region. Finally, five classes from each school (a total of 30 classes) were randomly chosen (one class from every grade). All the schools were coeducational.

Instrumentation

The Aggression Questionnaire (Buss & Perry, 1992) was employed to assess aggressive behavior. The Aggression Questionnaire is a 29-item instrument, which assesses four dispositional subtraits of aggression, namely, physical aggression, verbal aggression, anger, and hostility. “Physical and verbal aggression, which involve hurting or harming others, represent the instrumental or motor component of behavior. Anger, which involves physiological arousal and preparation for aggression, represents the emotional or affective component of behavior. Hostility, which consists of feelings of ill will and injustice, represents the cognitive component of behavior’’ (Buss & Perry, 1992, p. 457). An example of physical aggression item is, “If someone hits me, I hit back”; an example of a the verbal aggression item is, “I often find myself disagreeing with people”; an example of the anger item is, “I sometimes feel like a powder keg ready to explode”; and an example of the hostility item is, “I wonder why sometimes I feel so bitter about things.” A 5-point Likert-type scale (from 1 = not at all to 5 = completely) is used to record the extent to which respondents perceive the items of the questionnaire as representative of them. The translation and adaptation procedure and the psychometric properties of the GAQ have been described in details elsewhere (Tsorbatzoudis, 2006). The results of those studies indicated that internal consistency for all scales ranged from .69 to .80 and that all fit indices were at acceptable levels (comparative fit index [CFI] = .947, goodness-of-fit index [GFI] = .911, nonnormed fit index [NNFI] = .912, standardized root mean square residual [SRMR] = .077, root mean square error of approximation [RMSEA] = .052, 90% confidence interval [CI] of RMSEA = 0.044-0.059).

Procedure

Written permission from parents or guardians/caregivers was explicitly requested at the outset of the study. Students were invited to participate as volunteers in the study. Both oral and written instructions were given concerning the completion of the questionnaire. Also, following international guidelines for ethics in behavioral research, confidentiality and anonymity were assured (identifying information was not made available to anyone except the first author), and students were informed about the aims and purposes of the study, as well as their right to withdraw at any time without any foreseeable penalties or other consequences. No incentives were given to participants. Students completed the questionnaires in the class during school hours. The survey took approximately 20 min to complete. Three weeks later, a part of the original sample participants who were randomly selected (n = 119, M = 15.9, SD = 1.1) completed the same questionnaire. The study received approval by the Greek Ministry of Education, the principals, and the Teachers’ Board of Schools.

Results

Parents’ education and occupation status showed that they mainly belonged to middle- and upper-middle-class backgrounds. Ninety-four percent of the total sample participants were native Greeks and 6% belonged to other nationalities.

Descriptive Statistics

Means, standard deviations for males and females in Aggression Questionnaire scales and loadings are shown in Table 1. Internal consistency coefficients of the subscales were satisfactory for all the variables (α = .84 for physical aggression, α = .72 for verbal aggression, α = .71 for anger, and α = .70 for hostility).

Table 1.

Means, Standard Deviations for Males (n ₁ = 321) and Females (n ₂ = 337) in Aggression Questionnaire Scales and Standardized Coefficients (SC) with Correlations Coefficients (CC) of the Discriminant Function.

	Males		Females
Variables	M	SD	M	SD	CC	SC
Physical aggression	28.09	6.96	22.72	6.59	−.61	−1.14
Verbal aggression	15.24	3.66	15.17	3.89	−.02	.11
Anger	21.49	5.12	23.32	5.21	.27	.75
Hostility	24.60	5.40	26.75	5.57	.30	.33

Gender and Age Differences

Discriminant analysis was used to identify the variables that are able to distinguish aggression between genders. Physical aggression, verbal aggression, anger and hostility were entered as independent variables. The analysis yielded a significant discriminant function (Wilks’ Lambda = .71, χ² = 228.65, df = 4, p < .001). The canonical correlation between the discriminant function and the two groups was .54. The reliability of this function was determined from the percentage of individuals who were correctly classified. In total, 75.7% of the boys and 70.9% of the girls from the original group cases were correctly classified. The pooled within-group correlations between discriminating variables and standardized canonical discriminant function indicated that the main variable discriminating boys and girls was physical aggression. The analysis indicated a small contribution of hostility and anger, whereas verbal aggression had no contribution at all to this discriminant function. However, isolated discriminant analysis using the same independent variables showed that the percentages of correctly classified high school boys and girls varied across 7th (age 12), 8th (age 13), 9th (age 14), 10th (age 15), and 11th (age 16) grades (71.1 to 76.8%, 73.1 to 91.0%, 74.4 to 68.8%, 75.5 to 67.0%, and 74.6 to 68.3%, respectively).

In an effort to estimate the stability of the classification results from the discriminant function analysis, a cross-validation with the sample of the second time measure was employed. The discriminant function analysis was rerun to estimate the stability of the classification rates. The analysis resulted in an overall rate of 74.6% for boys’ and 66.7% for girls’ correct classification (Wilks’ Lambda = .75, χ² = 29.15, df = 4, p < .001).

Gender and Age Interaction

Gender by Age (2 x 5) between-subjects analyses of variances (ANOVAs) were conducted to examine physical aggression, verbal aggression, anger and hostility. The ANOVAs indicated that, for physical aggression and anger, there were statistical significances for (a) gender: aggression—F(1, 648) = 111.72, p < .0001, partial η² = .147, and anger—F(1, 648) = 17.91, p < .0001, partial η² = .027; (b) age: aggression—F(4, 648) = 4.995, p = .001, partial η² = .030, and anger—F(4, 648) = 5.63, p < .001, partial η² = .034; and (c) Gender by Age interaction: aggression—F(4, 648) = 5.76, p < .0005, partial η² = .034, and anger—F(4, 648) = 4.87, p = .001, partial η² = .029. The ANOVA results showed that for (a) verbal aggression there were statistical significance for age, F(4, 648) = 3.98, p = .003, partial η² = .024, and nonsignificance for gender, F(1, 648) = .871, p = .351, partial η² = .001, and Gender by Age interaction, F(4, 648) = 2.22, p = .065, partial η² = .014, and for (b) hostility, there were statistical significance for gender, F(1, 648) = 22.86, p < .0001, partial η² = .034, and nonsignificance for age, F(4, 648) = .544, p = .703, partial η² = .003, and Gender by Age interaction, F(4, 648) = .970, p = .423, partial η² = .006. Bonferroni post hoc analysis for the significant interactions showed that (a) males reported significantly higher values than females on physical aggression in all ages, and (b) females reported significantly higher values than males on anger in ages 15 and 16 years. Bonferroni post hoc analysis for age main effect on verbal aggression indicated that students aged 12 (Grade 7; M = 14.17, SD = 3.95) reported lower values than students aged 14 (Grade 9; M = 15.60, SD = 3.38), 15 (Grade 10; M = 15.68, SD = 3.78), and 16 (Grade 11; M = 15.65, SD = 4.01). The rest of the paired comparisons did not reach statistical significance. Moreover, the statistical significance for gender main effect on hostility was due to higher values reported by females (M = 26.75, SD = 5.57) as compared to males (M = 24.60, SD = 5.40). Mean scale scores and standard deviations as well as mean differences, standard errors, and significance for statistically significant interactions for each age by gender are presented in Table 2.

Table 2.

Mean Scale Scores, Standard Deviations (d Values, Standard Errors, and Statistical Significance for Significant Interactions) Between Males and Females at Different Ages for Aggression Variables.

		Males			Females
Scale	Age	M	SD	n	M	SD	n	d	SE	p
Physical aggression	12	26.46	5.95	83	20.23	7.14	56	6.23	1.14	.000
	13	30.54	7.66	52	21.03	3.95	67	9.51	1.22	.000
	14	29.94	7.53	78	23.55	8.44	77	6.39	1.06	.000
	15	27.35	6.04	49	24.02	4.47	55	3.33	1.30	.01
	16	26.41	6.54	59	24.16	6.51	82	2.25	1.13	.046
Verbal aggression	12	14.28	3.55	83	14.02	4.50	56	—	—	—
	13	15.90	3.73	52	14.24	3.29	67	—	—	—
	14	15.33	2.94	78	15.87	3.77	77	—	—	—
	15	16.08	3.86	49	15.33	3.72	55	—	—	—
	16	15.20	4.20	59	15.96	3.87	82	—	—	—
Anger	12	19.86	4.74	83	21.50	5.15	56	1.65	.87	.059
	13	22.71	6.19	52	21.97	3.75	67	.74	.93	.425
	14	23.15	4.34	78	23.51	6.24	77	.35	.81	.663
	15	21.37	4.54	49	24.46	4.70	55	3.09	.99	.002
	16	20.63	5.22	59	24.73	5.00	82	4.11	.86	.000
Hostility	12	24.34	5.71	83	26.54	6.47	56	—	—	—
	13	24.19	5.75	52	26.46	5.30	67	—	—	—
	14	25.13	5.37	78	26.35	5.49	77	—	—	—
	15	24.84	4.81	49	26.07	4.48	55	—	—	—
	16	24.46	5.26	59	27.95	5.79	82	—	—	—

Discussion

The aim of the present study was to examine gender and age differences in aggressive behavior with Greek high school students. In addition, the discriminating ability of the GAQ was tested. The findings indicated that gender and age had a significant interaction effect for different types of aggression and that physical aggression was the most powerful discriminating variable between boys and girls.

Regarding physical aggression, Edmunds and Kendrick (1980) reported similar findings using the Buss–Durkee Hostility Inventory. They found that the aggression factor was able to discriminate between people with high and low aggressiveness, whereas the hostility factor was not able to make such a discrimination. The subscale of physical aggression used in the present study includes items assessing provocation, hitting, fighting, threatening people, breaking things, and so on. It seems that Greek high school students identify aggression mainly with its physical type. This may be due to the fact that physical forms of aggression are more easily observed than the other forms measured with the questionnaire. Finally, the fact that the percentages of the second sample for boys and girls were very similar to those of the first sample suggests that the classification results were relatively robust against sampling fluctuations. Similar percentages could be found in published studies examining gender differences in attitudes (Bebetsos, Papaioannou, & Theodorakis, 2003).

To summarize, the findings of the study regarding the discriminatory power of the Aggression Questionnaire partially supported the first hypotheses of the study. Overall, the detailed examination of the instrument’s discriminatory power provided support for the hypothesis that physical aggression can discriminate between genders. Future research should attempt to discriminate among different kinds of criminals, alcohol-related aggression with a focus on high school students, or aggression as a result of using illegal substances.

The analysis of variance indicated gender differences on aggression factors in various ages. As expected, males scored higher in physical aggression than females. On the other hand, the pattern of mean scores in anger and hostility was reversed. No gender differences for verbal aggression in Greek high school students were found. In general, the results of the analyses of variance were consistent with those of the discriminant function analysis.

The finding that males were more physically aggressive than females has been repeatedly reported in other studies (Archer, Holloway, & McLoughlin, 1995; Bettencourt & Miller, 1996; Buss & Perry, 1992; Harris, 1995b, 1996; Toldos, 2005). Moreover, the finding regarding the affective (anger) and the cognitive component (hostility) of aggression poses the question whether this is a result of the Greek school system or whether it is due to cultural variation. These results may also suggest that gender-role stereotypes influence the recall of aggressive behaviors. This hypothesis is supported by Crick, Bigbee, and Howes (1996), and Smith, Rose, and Schwartz-Mette (2010), who found that older girls consider relational aggression to be more normative than younger girls.

Some researchers attribute considerable meaning to findings regarding physical aggression, and refer to an “intimate connection” between masculinity and aggression (Campbell, 1993). Some others make reference to the Darwinian sexual selection theory (Archer, 2009; Archer et al., 1995), which proposes that males compared to females are more likely to engage in escalated physical aggression and that this pattern declines with age.

Research endeavors should explore the question whether physical aggression of school boys is due to physical competencies and motor skills and to greater capacity to inflict injury and girls’ lesser capacity to resist it. Some support has been offered by Askew’s findings, who underlined the importance of masculine characteristics such as strength and competitiveness in the explanation of aggressiveness. This is an important line of research as it is possible that size or strength, physical competencies, and motor skills may influence the expression of aggressiveness (Askew, 1989; Archer & Thanzami, 2007). In fact, this may be essential for understanding and explaining the aggressive behavior of adolescents in school settings. Thus, future research should clarify the role of the social interaction processes in and outside the school and the role of physical competencies and motor skills in the initialization and expression of aggression.

The findings of the present study regarding verbal aggression contradict those of Owens and MacMullin (1995), who found that Grade 9 girls (age 14) were rated by their peers as using more verbal aggression than girls of higher grades. It may be that boys deal with the strains and stressors or stress of the transition period during adolescence by being more verbally aggressive with each other, as they work to understand how relationships change in the teen years. Again, more studies are needed to determine the borderlines of this trend.

In the present study, girls showed higher mean scores in anger and hostility than boys in all grades (except Grade 8—age 13, for anger). These findings are consistent with previous research suggesting that indirect forms of aggression are more typical of women than of men (Björkvist, Osterman, & Lagerspetz, 1994; Hess & Hagen, 2006; Hines & Fry, 1994). This result poses questions about the use of coping strategies in school and daily life interactions of students. It is well known that special kinds of interactions could be produced in physical education courses. In this way, the role of physical education and sports should be questioned, considering that different aggression subtraits are the result of learning processes. Do specific physical education contents promote aggressive acts? What kind of coping strategies could students in physical education classes use to prevent aggressive acts? The answer to those questions seems to be essential both for the person itself and the social educational environment (teachers and physical education teachers, school psychologists, etc.).

Results also indicated that the pattern of gender differences in verbal aggression, anger, and hostility is less clear for adolescents. Although some researchers have found that males are more verbally aggressive than females (Buss & Perry, 1992; Eagly & Steffen, 1986; Harris, 1992; Nakano, 2001; von Collani & Werner, 2005), others pointed out that differences in verbal aggression are less common than differences in physical aggression (Frodi et al., 1977). Regarding the lack of gender differences on verbal aggression, studies examining direct verbal aggression separately from physical aggression have also found no gender differences (Pelham, Richard, Murphy, & Murphey, 1989). However, researchers who combined direct verbal aggression with direct physical aggression have found higher levels of verbal aggression among boys, compared to girls (Björkvist, Lagerspetz, & Kaukianen, 1992). Evaluating similar findings, Eagly and Steffen in their meta-analysis concluded that gender differences on aggression are a function of perceived consequences of aggression that are learned as aspects of gender roles and other social roles. Like other social behaviors, aggression can be viewed as a role behavior (for a review, see Archer, 2009). Therefore, it could be regulated by the social norms that people have to abide. To explain gender differences one must understand the ways in which aggression is sustained or inhibited by each gender’s social roles. The social role of male encourages demonstration of aggression, whereas the traditional role of female places little emphasis on aggressiveness (Campbell, 2006). In addition, female role emphasizes the avoidance of provoking physical harm to someone, and females are associated with care and tenderness (White, 1983) and parental investment (Campbell, 1999).

The present findings suggest that males compared to females used direct forms of aggression (e.g., physical aggression) whereas females tend to prefer more indirect forms of aggression (e.g., anger and hostility). Thus, future research should be geared specifically to the experiences of girls, rather than trying to assess female adolescent aggression through the lens of male adolescent aggression. Research examining associations between encouragement of different forms of aggression in boys and girls from the social environment (parents, teachers, team, and contact sports, etc.) and the mediating role of social cognitions to the formation of direct and indirect forms of aggression is required. Hence, more personal and environmental variables that might affect aggression during adolescence, such as anxiety in different courses, community size, and athletic involvement, should be examined in future studies.

In summary, the study added to the existing knowledge in gender and grade interaction while they confirmed that the role of school boys corresponds to the expression of physical aggression and that the indirect forms of aggression observed in school settings characterize more the school girls’ behavior of higher grades. Due to possible cultural variations in development, understanding, and expression of different aggressive forms (Archer & Thanzami, 2007; Markus & Kitayama, 1991), replication with larger, more diverse samples is necessary to determine the generalizability of the present results. Longitudinal studies and observational measures are also recommended to explore whether any of these characteristics fluctuate across time. These findings will in turn assist in the development of effective school-based interventions and preventive programs aiming to alter specific components of aggression (hostility, anger, etc.) in order to provide a safe school and sport environment conducive to learning and enhancing the physical, emotional, and social well-being of the students.

Footnotes

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Author Biographies

Antonios K. Travlos is an associate professor in the Department of Sport Management at the University of Peloponnese, Greece. His current research interests include aggression, bullying, violence in sports, anxiety, stress management, and schedule of practice.

Haralambos Tsorbatzoudis is a professor in the Department of Physical Education and Sports Sciences at Aristotle University of Thessaloniki, Greece. His research interests are in motivation, anxiety, aggression, self-concept in athletes, and doping.

Angelos Rodafinos is head of the psychology department at Swinburne University of Technology, Melbourne, Australia. His research interests include smoking, stress and coping, persuasion, motivation, academic achievement, and job satisfaction.

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