Van Lange et al. propose an interesting new model to help explain global patterns of aggression with their CLASH model. Given the global nature of CLASH's predictions, it may be useful to apply it to a global form of aggression: bullying. Bullying can be defined as an “aggressive goal-directed behavior that harms another individual within the context of a power imbalance” (Volk et al. Reference Volk, Dane and Marini2014). Globally, between 100 and 600 million adolescents are estimated to be involved in bullying as perpetrator or victim (Volk et al. Reference Volk, Craig, Boyce and King2006). Bullying therefore appears to be a ubiquitous behavior that causes significant harm on a global scale (Wolke & Lereya Reference Wolke and Lereya2015).
One of the stronger arguments for the ubiquity of bullying is that it is an evolved behavior that can be found in all cultures, times, and places where sufficient data exist (Volk et al. Reference Volk, Camilleri, Dane and Marini2012). To support this argument, in part, I have used two ethnographies as extreme examples: “Never in Anger” (Briggs Reference Briggs1970; Inuit in the Canadian Arctic) and “The Harmless People” (Thomas Reference Thomas1989; !Kung in the Kalahari desert). Both explicitly describe their groups as peaceful and non-aggressive, yet bullying can still be observed within these groups. However, the bullying reported in these “peaceful” cultures is generally less risky, indirect, or social bullying (e.g., spreading rumors, excluding others), as compared with the more overt and violent bullying (e.g., punching, kicking, direct verbal insults) observed in other hunter-gatherer groups who live in less extreme environments (e.g., Yanomamo [Chagnon Reference Chagnon1983; Chagnon personal communication 2013]; Ik [Turnbull Reference Turnbull1972]). These qualitative data support a curvilinear CLASH model for average temperatures whereby the climatic stressors found in extreme environments moderate bullying toward less overt and severe forms.
To further explore the link between the CLASH model and bullying, I analyzed data from the largest cross-cultural study on bullying (Craig et al. Reference Craig, Harel-Fisch, Fogel-Grinvald, Dostaler, Hetland, Simons-Morton, Molcho, de Mato, Overpeck, Due and Pickett2009). Across 40 European and North American countries, for both boys (r
s = 0.34, p < .05) and girls (r
s = 0.34, p < .05), there was a significant positive correlation between the prevalence of bullying and proximity to the equator (as ranked by 10° latitude bands). To my knowledge, this is the first time that anyone has examined whether bullying is related to geographic latitude/climate factors, and reveals an important source of variation that has so far been overlooked by bullying researchers. It also offers potential further quantitative support for the CLASH model. I say “potential support” because it is important to note Van Lange et al.'s cautions about using CLASH for comparison of between-country prevalence rates, but the relatively robust effect sizes suggest a novel step in explaining the variance associated with the prevalence of bullying, and an interesting new line of inquiry for bullying research.
However, a link between bullying and climate also somewhat contrasts with the CLASH model. Bullying is a largely proactive form of aggression (Volk et al. Reference Volk, Dane and Marini2014), whereas the CLASH model aims at explaining largely reactive forms of aggression caused by poor self-control. I therefore wonder whether CLASH-associated Life History Theory (LHT) solely explains reactive aggression or whether it better explains impulsive aggression that might include reactive and/or overt forms aggression. Multivariate models equating LHT with personality traits suggest that a fast LHT (as proposed by CLASH) is more strongly associated with lower Extraversion and Conscientiousness rather than tendencies to engage in proactive aggression (Honesty-Humility), or especially to react aggressively to provocation (Agreeableness [Strouts et al. Reference Strouts, Brase and Dillon2016]). I therefore propose that CLASH may be tapping into a dimension of antisocial carelessness that leads to an increase in overt, as well as possibly reactive, forms of aggression. This lack of conscientious control suggests that the link between CLASH and reactive aggression may be due to confounding variables (low Extraversion and Conscientiousness) instead of an increased tendency to be reactive toward provocation (low Agreeableness). In support of this, the higher levels of overt physical bullying found in warmer climates (e.g., Chagnon Reference Chagnon1983) may be best predicted by low levels of Conscientiousness, not Agreeableness (Farrell et al. Reference Farrell, Della Cioppa, Volk and Book2014). I therefore suggest that further tests of the CLASH model incorporate an emphasis on different forms of aggression beyond reactive aggression. As a form of general aggression, bullying may offer an excellent format for testing CLASH's ability to predict proactive, reactive, covert, and overt forms of aggression along with their personality correlates (Farrell et al. Reference Farrell, Della Cioppa, Volk and Book2014). The CLASH model thus receives some support from bullying research while provoking further research questions from that literature. Given the importance of the outcomes of bullying (Wolke & Lereya Reference Wolke and Lereya2015), Van Lange et al. add new lines of inquiry that are a welcome addition to growing efforts aimed at reducing or preventing bullying.
Van Lange et al. propose an interesting new model to help explain global patterns of aggression with their CLASH model. Given the global nature of CLASH's predictions, it may be useful to apply it to a global form of aggression: bullying. Bullying can be defined as an “aggressive goal-directed behavior that harms another individual within the context of a power imbalance” (Volk et al. Reference Volk, Dane and Marini2014). Globally, between 100 and 600 million adolescents are estimated to be involved in bullying as perpetrator or victim (Volk et al. Reference Volk, Craig, Boyce and King2006). Bullying therefore appears to be a ubiquitous behavior that causes significant harm on a global scale (Wolke & Lereya Reference Wolke and Lereya2015).
One of the stronger arguments for the ubiquity of bullying is that it is an evolved behavior that can be found in all cultures, times, and places where sufficient data exist (Volk et al. Reference Volk, Camilleri, Dane and Marini2012). To support this argument, in part, I have used two ethnographies as extreme examples: “Never in Anger” (Briggs Reference Briggs1970; Inuit in the Canadian Arctic) and “The Harmless People” (Thomas Reference Thomas1989; !Kung in the Kalahari desert). Both explicitly describe their groups as peaceful and non-aggressive, yet bullying can still be observed within these groups. However, the bullying reported in these “peaceful” cultures is generally less risky, indirect, or social bullying (e.g., spreading rumors, excluding others), as compared with the more overt and violent bullying (e.g., punching, kicking, direct verbal insults) observed in other hunter-gatherer groups who live in less extreme environments (e.g., Yanomamo [Chagnon Reference Chagnon1983; Chagnon personal communication 2013]; Ik [Turnbull Reference Turnbull1972]). These qualitative data support a curvilinear CLASH model for average temperatures whereby the climatic stressors found in extreme environments moderate bullying toward less overt and severe forms.
To further explore the link between the CLASH model and bullying, I analyzed data from the largest cross-cultural study on bullying (Craig et al. Reference Craig, Harel-Fisch, Fogel-Grinvald, Dostaler, Hetland, Simons-Morton, Molcho, de Mato, Overpeck, Due and Pickett2009). Across 40 European and North American countries, for both boys (r s = 0.34, p < .05) and girls (r s = 0.34, p < .05), there was a significant positive correlation between the prevalence of bullying and proximity to the equator (as ranked by 10° latitude bands). To my knowledge, this is the first time that anyone has examined whether bullying is related to geographic latitude/climate factors, and reveals an important source of variation that has so far been overlooked by bullying researchers. It also offers potential further quantitative support for the CLASH model. I say “potential support” because it is important to note Van Lange et al.'s cautions about using CLASH for comparison of between-country prevalence rates, but the relatively robust effect sizes suggest a novel step in explaining the variance associated with the prevalence of bullying, and an interesting new line of inquiry for bullying research.
However, a link between bullying and climate also somewhat contrasts with the CLASH model. Bullying is a largely proactive form of aggression (Volk et al. Reference Volk, Dane and Marini2014), whereas the CLASH model aims at explaining largely reactive forms of aggression caused by poor self-control. I therefore wonder whether CLASH-associated Life History Theory (LHT) solely explains reactive aggression or whether it better explains impulsive aggression that might include reactive and/or overt forms aggression. Multivariate models equating LHT with personality traits suggest that a fast LHT (as proposed by CLASH) is more strongly associated with lower Extraversion and Conscientiousness rather than tendencies to engage in proactive aggression (Honesty-Humility), or especially to react aggressively to provocation (Agreeableness [Strouts et al. Reference Strouts, Brase and Dillon2016]). I therefore propose that CLASH may be tapping into a dimension of antisocial carelessness that leads to an increase in overt, as well as possibly reactive, forms of aggression. This lack of conscientious control suggests that the link between CLASH and reactive aggression may be due to confounding variables (low Extraversion and Conscientiousness) instead of an increased tendency to be reactive toward provocation (low Agreeableness). In support of this, the higher levels of overt physical bullying found in warmer climates (e.g., Chagnon Reference Chagnon1983) may be best predicted by low levels of Conscientiousness, not Agreeableness (Farrell et al. Reference Farrell, Della Cioppa, Volk and Book2014). I therefore suggest that further tests of the CLASH model incorporate an emphasis on different forms of aggression beyond reactive aggression. As a form of general aggression, bullying may offer an excellent format for testing CLASH's ability to predict proactive, reactive, covert, and overt forms of aggression along with their personality correlates (Farrell et al. Reference Farrell, Della Cioppa, Volk and Book2014). The CLASH model thus receives some support from bullying research while provoking further research questions from that literature. Given the importance of the outcomes of bullying (Wolke & Lereya Reference Wolke and Lereya2015), Van Lange et al. add new lines of inquiry that are a welcome addition to growing efforts aimed at reducing or preventing bullying.