Writer: Sunny Liu
Editor: Ulya Aligulova
Recent years seem to be more violent. We often think of the “Good Old Days”, while the current generation is “lazy”, “violent”, and “spoiled”. It is easy to think about violence in recent days – the 2016 Presidential Campaign in the United States was marred with misogyny, racism, xenophobia, and, how can we forget, allegations of “golden showers”. The Brexit referendum was similarly decorated with lies and bigotry. The “Brexit” campaign led by a man with terrible hair, while the “Remain” campaign was led by a man who couldn’t care less. Knife crime has been increasing in the UK, with even teenagers falling victims to the stabbing epidemic.
Why do we think the past is better? Recency effects and rosy retrospection bias in psychology aside, there could be a climate-related effect on this increased aggression. Given rising average global temperature, this might account for the increased violence we’ve witnessed in recent years. This is what this month’s column, links between weather and aggressive behaviour, is all about.
Ambient temperatures have an inverted-U relationship with many outdoor recreational activities (think jogging). It makes sense – most of us are likelier to go for a jog in spring/autumn. We very much prefer to cuddle indoors with a mug of hot cocoa when it’s cold and have a cold beer with the Air Conditioning on when it’s hot out.
There is a simple reason for this – it’s comfy. In biological terms, the body expends more energy in extreme temperatures to maintain a constant physiological temperature. In psychological terms, it can become a form of stress, as more mental resources are needed to stay focused. And, much like stresses from deadlines, relationships, and parents, they add up. Seyle’s Theory of General Adaptation suggests that the body responds to all stresses similarly, via the same “fight-or-flight” pathway regardless of the source of stress, as the body releases the same stress hormone regardless of stressor. This can lead to symptoms such as depression and aggressive behaviour. Why?
Seyle’s Theory of General Adaptation postulates that there are three stages of stress – Alarm, Resistance, and Exhaustion. The Alert stage occurs upon the perception of a stressor. In the second stage, Resistance, the body attempts to compensate the stress response by modulating other physiological functions back to normal while dealing with the stressor. However, if the stressor(s) remain, the body’s resources, including that of the brain’s resources, may be worn out, leading to Exhaustion – aka a “burn out”. Under increased stress from a warmer climate, it is easier to “burn out” as one is under more stress. Thus, it is predicted that the prevalence of stress symptoms such as depression and suicide increases. Aggressive behaviours may also occur as the inhibitor resources of the brain (that prevents one from throwing a punch or starting fights) are lacking since the same mental resources are utilized to handle heat stresses caused by climate change.
Indeed, since the early 1970s, psychologists have explored the relationship between heat and aggression. In 1986, Dr. Douglas T. Kenrick’s lab demonstrated a linear correlation between heat and aggression. From April to August, they held experiments involving 75 subjects on a narrow road. A female confederate would intentionally drive terribly to instigate the subjects, and the latter’s behaviours were observed; in particular, Dr. Kenrick recorded the number of honks, duration of each honk, and latency to first honk. Moreover, information such as the number of passengers, number of cars behind the subjects, and whether the car windows were open or closed were recorded. Working together with a Geography department, they calculated the readings of temperature and humidity to determine a combined discomfort index. The results demonstrated a direct linear relationship, with increased horn-honking associated with higher discomfort index. The results were stronger when the subjects’ windows were rolled down (and presumably not operating their in-car air conditioning unit).
These findings were not exclusive to the state of Arizona in the United States. In Australia, Dr. Heather R. Stevens demonstrated significant increases in assault and theft with rising temperature. In Quebec, Canada, the number of visits to emergency departments for mental and psychosocial problems increased with higher mean temperature and humidity. Even in controversial actions such as suicide (controversial due to the multifactor nature of suicide), Dr. Lisa A. Page concluded an increased risk of suicide in hot weather.
It is not new that climate change will cause increased global temperatures; however, it is clear that we are unaware of the full costs. They are higher than expected. Aside from ecological and human cost in diseases, poverty, and food insecurity, the psychological effect of climate change has been underreported in the media. In 2014, Dr. Matthew Ranson ran a systematic analysis based on a 30-year data of monthly crime and weather. He estimated the numbers of crime linked to increased temperature due to climate change. The figures are staggering: in just the United States, between 2010 to 2099, climate change will cause an additional 22,000 murders, 2.3 million simple assaults, 1.2 million aggravated assaults, and millions of other crimes.
As we are already aware, global climate change is a serious concern. However, aside from salient ecological costs of maladaptive animals and the human costs from natural disasters, we must acknowledge the psychological costs and effects that it will have on society, keeping in mind that the prior analyses have yet to address the psychological costs of natural disasters on a populace. We cannot simply pressure the ostriches in our parliament – we must practice personal responsibility. Other than recycling, switching off lights, planting more trees, there’s plenty more that we can do!