Summary: Hotter temperatures and climates that have less seasonal variation in temperatures have an impact on aggression, a new study reports.
Source: Ohio State University.
Climate impacts life strategies, time orientation, and self-control.
Researchers have long struggled to explain why some violent crime rates are higher near the equator than other parts of the world. Now, a team of researchers have developed a model that could help explain why.
This new model goes beyond the simple fact that hotter temperatures seem to be linked to more aggressive behavior.
The researchers believe that hot climates and less variation in seasonal temperatures leads to a faster life strategy, less focus on the future, and less self-control – all of which contribute to more aggression and violence.
“Climate shapes how people live, it affects the culture in ways that we don’t think about in our daily lives,” said Brad Bushman, co-author of the study and professor of communication and psychology at The Ohio State University.
Paul van Lange, lead author of the study and a professor of psychology at the Vrije Universiteit Amsterdam (VU) added, “We believe our model can help explain the impact of climate on rates of violence in different parts of the world.”
The researchers, which included Maria I. Rinderu of VU, call the new model CLASH (CLimate Aggression, and Self-control in Humans). They describe the CLASH model in an online article in the journal Behavioral and Brain Sciences.
Many studies have shown that levels of violence and aggression are higher in hot climates, according to the researchers.
“But the two leading explanations of why that is so aren’t satisfactory”, Bushman said.
The General Aggression Model (which Bushman helped develop) suggests hot temperatures make people uncomfortable and irritated, which makes them more aggressive. “But that doesn’t explain more extreme acts, such as murder”, he said.
Another explanation (Routine Activity Theory) is that people are outdoors and interacting more with others when the weather is warm, which leads to more opportunities for conflict. But that doesn’t explain why there’s more violence when the temperature is 95 degrees F (35 °C) than when it is 75 degrees F (24 °C) – even though people might be outside under both circumstances.
The CLASH model states that it is not just hotter temperatures that lead to more violence – it is also climates that have less seasonal variation in temperature.
“Less variation in temperature, combined with heat, brings some measure of consistency to daily life”, Rinderu said.
That means there is less need to plan for large swings between warm and cold weather. The result is a faster life strategy that isn’t as concerned about the future and leads to less need for self-control.
“Strong seasonal variation in temperature affects culture in powerful ways. Planning in agriculture, hoarding, or simply preparing for cold winters shapes the culture in many ways, often with people not even noticing it. But it does shape how much a culture values time and self-control,” Van Lange said.
“If there is less variation, you’re freer to do what you want now, because you’re not preparing foods or chopping firewood or making winter clothes to get you through the winter. You also may be more concerned with the immediate stress that comes along with parasites and other risks of hot climates, such as venomous animals.”
People living in these climates are oriented to the present rather than the future and have a fast life strategy – they do things now.
“We see evidence of a faster life strategy in hotter climates with less temperature variation – they are less strict about time, they have less use of birth control, they have children earlier and more often,” Bushman said.
With a faster life strategy and an orientation toward the present, people have to practice less self-control, he said. That can lead people to react more quickly with aggression and sometimes violence.
The theory is not deterministic and isn’t meant to suggest that people in hotter, consistent climates can’t help themselves when it comes to violence and aggression.
“How people approach life is a part of culture and culture is strongly affected by climate,” Van Lange said. “Climate doesn’t make a person, but it is one part of what influences each of us. We believe it shapes the culture in important ways,” he said.
Since CLASH is a new theory, studies have to be done to prove it is correct. But Bushman said a lot of evidence already suggests that the theory may be on to something.
“We believe CLASH can help account for differences in aggression and violence both within and between countries around the world,” he said. “We think it provides a strong framework for understanding the violence differences we see around the world.”
Source: Brad Bushman – Ohio State University
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Original Research: Abstract for “Aggression and Violence Around the World: A Model of CLimate, Aggression, and Self-control in Humans (CLASH)” by Paul A. M. Van Lange, Maria I. Rinderu and Brad J. Bushman in Behavioral and Brain Sciences. Published online May 23 2016 doi:10.1017/S0140525X16000406
Aggression and Violence Around the World: A Model of CLimate, Aggression, and Self-control in Humans (CLASH)
Worldwide there are substantial differences within and between countries in aggression and violence. Although there are various exceptions, a general rule is that aggression and violence increase as one moves closer to the equator, which suggests the important role of climate differences. While this pattern is robust, theoretical explanations for these large differences in aggression and violence within countries and around the world are lacking. Most extant explanations focus on the influence of average temperature as a factor that triggers aggression (The General Aggression Model), or the notion that warm temperature allows for more social interaction situations (Routine Activity Theory) in which aggression is likely to unfold. We propose a new model of CLimate, Aggression, and Self-control in Humans (CLASH) that seeks to understand differences within and between countries in aggression and violence in terms of differences in climate. Lower temperatures, and especially larger degrees of seasonal variation in climate, calls for individuals and groups to adopt a slower life history strategy, and exert more focus on the future (versus present), and a stronger focus on self-control. The CLASH model further outlines that slow life strategy, future orientation, and strong self-control are important determinants of inhibiting aggression and violence. We also discuss how CLASH is different from other recently developed models that emphasize climate differences for understanding conflict. We conclude by discussing the theoretical and societal importance of climate in shaping individual and societal differences in aggression and violence.
“Aggression and Violence Around the World: A Model of CLimate, Aggression, and Self-control in Humans (CLASH)” by Paul A. M. Van Lange, Maria I. Rinderu and Brad J. Bushman in Behavioral and Brain Sciences. Published online May 23 2016 doi:10.1017/S0140525X16000406