A study in Spain found that adolescents with high levels of the hormones testosterone and cortisol as well as adolescents with low levels of these hormones react more aggressively when they are victimized or provoked by peers. In girls, the ratio of these two hormones was also associated with aggressive responses. The study was published in Development and Psychopathology.
Peer victimization refers to situations when an adolescent or a child is exposed to negative actions by one or more peers. It can take many forms – bullying and physical aggression, relational victimization (such as when an adolescent/child is excluded from the peer group), direct insults and humiliation, and others. It is mostly studied in the school context. Research indicates that between 15% and 35% of children and adolescents experience peer victimization.
One relatively novel form of peer victimization is online aggression or cyberbullying. Cyberbullying consists of repeatedly sending offensive messages to the victim or posting videos or messages about the victim on social networks. Peer victimization is associated with worsening of different self-related perceptions such as self-esteem, self-blame, and self-worth.
Many adolescents react aggressively to being the target of peer victimization. This can result in suffering victimization and inflicting victimization on others appearing at the same time and in the same individual. In this way, conditions are created that allow victimization to perpetuate over time. Due to this, examining factors that determine whether a person suffering peer victimization will react aggressively can contribute to developing ways to prevent or stop peer victimization.
The authors of this study wanted to explore whether levels of testosterone and cortisol jointly moderate the aggressive behaviors that appear as responses to peer victimization.
“After decades of research on the association between testosterone and aggression in humans, several meta-analyses indicate that the results remain inconclusive,” said study author Esther Calvete, a professor of psychology at the University of Deusto. “Further, these meta-analyses point out that previous research has important methodological limitations, such as insufficient sample sizes and a paucity of longitudinal designs. Therefore, with this study we wanted to find answers about the role of testosterone in adolescent aggression.”
The researchers analyzed data from a study examining ways to prevent depression and other psychological problems in adolescents. Data in this study came from 577 adolescents, between 12 and 17 years of age, attending 10 schools in the Basque Country, Spain.
Participants completed assessments of offline victimization and perpetration of aggressive behavior (the Revised Peer Experiences Questionnaire), and online aggressive behavior perpetration and victimization (the Cyberbullying Questionnaire). Researchers collected participants’ saliva samples in the classrooms in order to assess their testosterone and cortisol levels.
Results showed that there was a very strong link between victimization and aggressive behavior perpetration. Participants who were victims of aggressive behavior were more likely to be aggressive themselves. The association was also strong between offline and online aggression. Adolescents who were aggressive offline tended to also be aggressive online and vice versa.
When Calvete and her colleagues examined associations between combinations of the two hormones, results showed that adolescents who had high levels of both hormones and those who had low levels of both hormones responded with more aggressive behaviors when victimized or provoked by peers online.
“Testosterone alone does not explain aggression in adolescents. Rather, it is when combined with other hormones and victimization experiences that it may contribute to adolescents’ violent reactions,” Calvete told PsyPost.
When offline aggression was considered, results showed that participants with high levels of both hormones responded with more aggression (as in the case of online victimization). However, results were less clear for participants with low levels of both hormones. Their aggressive reactions were more pronounced than those of participants with high testosterone and low cortisol levels, but not than those with low testosterone and high cortisol.
When researchers looked at findings on boys and girls separately, the results showed that when girls had high cortisol levels, higher levels of testosterone were associated with more aggressive online responses. However, when their cortisol levels were low, higher levels of testosterone were associated with less aggressive online responses.
When offline victimization was considered, testosterone and cortisol level combinations were associated with aggressive offline reactions in boys, but not in girls. Additionally, the ratio of concentrations of the two hormones in saliva was associated with online aggressive responses of girls, but not of boys.
“The results are opposite to those predicted by the dual hormone hypothesis, but they are consistent with the findings of other studies that examined aggressive behaviors as reactions to provocations. These results suggest that some combinations of testosterone and cortisol predict higher aggressive reactions to peer victimization,” the study authors concluded. (The dual hormone hypothesis proposes that testosterone is associated with aggressive behavior only when cortisol is low.)
The study sheds light on the link between hormone concentrations and complex behavior. However, it also has limitations that need to be taken into account. Notably, hormone concentration measures were taken only during one time of the day, although they are known to vary.
Additionally, assessments of victimization and perpetration were exclusively based on self-reports. These could have contributed to the strong association between assessments of victimization and aggressive behaviors. It is entirely possible that aggressive individuals like to present their aggression as a response to being victimized. It is also possible that victimized adolescents like to present that they respond to being victimized more than is actually the case.
“In our study, the association between testosterone and aggression depends on the situation (victimization and provocation experiences),” Calvete said. “However, as well as personal characteristics, such as gender, cortisol levels, and knowledge structures relevant to aggression. There are other factors such as psychological characteristics of adolescents that can interact with testosterone levels in predicting aggressive behavior. Our next steps are to investigate and identify these factors.”
The paper, “Do testosterone and cortisol levels moderate aggressive responses to peer victimization in adolescents?”, was authored by Esther Calvete and Izaskun Orue.