Why Do Humans Want To Kill Each Other?

Why Do Humans Want to Kill Each Other?

It may seem like humans are fair-minded, duty-driven, moral animals, compared to the wild species you see roaming savannahs or sneaking through jungles. But the data simply shows that it isn’t the case. In 2016 alone, there were over 17,000 murders in the United States. That’s just shy of fifty homicides every single day. The figure seems high, but it’s actually down from the early 1990s, when the USA was averaging around 20-25,000 murders a year. And these are stats for just a few decades in just one country. Imagine the millions more that have been murdered around the world throughout all of history.

The figures have been backed up, too. A 2016 study headed by zoologist Maria Gomez, and published in the journal “Nature”, suggested that humans have an evolutionary propensity for killing each other. Gomez’ team studied over 1,000 species of mammals and discovered that homo sapiens kill their own kind 7x as often as anything else. There are, of course, many things that distinguish us from every other animal, but that fact that we supposedly have a conscience is perhaps what makes Gomez’ findings a little surprising. We as humans can distinguish right from wrong, good from bad. We know morality, and we know that murder is definitely wrong. But despite this guide, humans kill other humans, and have done it for millennia. The conscience doesn’t kick in, or is ignored, far too often.

But, why exactly is that? The answer may lie in our basic biology. We’re animals, and lots of animals do have a tendency towards violence. According to some, humans are simply evolutionarily and biologically programmed to kill, and it’s linked to how our brains are inherently wired for survival. The fact that we kill more than others is neither here nor there.

Modern societies are a relatively new construct, with communities banding together at the advent of agriculture around 10,000 years ago. Before that, we lived in the wild. And, like most wild animals, we’re extremely territorial beings. As such, research has shown that territory can be motivation for murder in mammalian species. Just think about how often people resort to physical violence when their territory is intruded upon. On a small scale, we push people away if they breach our personal space. On a larger scale, home-owners have murdered trespassers in the event of a break-in. Territory is seen as a precious commodity, and people have killed other people whenever it appears threatened.

In a similar vein, humans are also a tribal species, both on the micro and macro level. We group together and create families. Families live within a specific village, town or city. These locations belong to a wider country. With each expansion the ‘tribe’ becomes larger, and often more difficult to define. Which sometimes throws us toward all types of political debate, especially around the issue of immigration and national borders. But beyond any one person’s political sway, the issues all too often fuel prejudiced and dangerous attitudes, with daily reports of violence or acts of hatred committed against anyone perceived as an ‘outsider’ to whichever tribe the perpetrator sees themselves as part of. As the anthropologist and ethnologist Claude Lévi-Strauss said, “humankind ceases at the border of the tribe, of the linguistic group, even sometimes of the village”. And of course, ‘politics plus territory’ also partly fuels perhaps the biggest platform throughout history for humans killing other humans: War.

The complex reasons why humans behave as they do are mounting up. But there’s another, seemingly simpler explanation, too: Rage. Author and neurobiologist R. Douglas Fields notes nine distinct triggers that often result in rage and the violence that follows, and they’re remembered by the acronym LIFEMORTS.

‘L’ stands for ‘life’. Essentially, it’s the idea that we will violently defend ourselves from potential physical harm. ‘I’ is ‘insult’, wherein we’re angered or feel threatened by what’s said or suggested. ‘F’ is ‘family’, ‘E’ equals ‘environment’ and ‘M’ is ‘Mate, which all link back to the territorial tendencies mentioned earlier. ‘O’ is ‘organization’, and relates to how blatant rule-breaking can infuriate some of us. ‘R’ is ‘resources’, and how the lack of them can lead to people employing desperate actions to get what they need. ‘T’ is the already touched upon ‘tribe’, and finally, ‘S’ is ‘stopped’ – referring to the retaliation rage we’re capable of whenever we feel trapped, restrained, or if aggressive behaviour is being aimed at us.

Unfortunately for us and those around us, we often give precedence to rage over rational thought. It all comes down to the neurocircuitry in our brains. The neural circuits responsible for rage and aggression are faster to act than our cerebral cortex, the region responsible for thought. This is a natural defense mechanism, as it allows us to override conscious thought and make split-second decisions. It’s similar to the fight-or-flight response we feel in dangerous or threatening situations. It’s why people are said to “explode” with rage, or they blackout and “see red”. And it’s why some murderers show regret for their decisions.

When we consider R. Douglas Fields’ LIFEMORTS checklist, we can see that there are plenty of potential triggers, but that many of them may stem from trivial things. However, when the rage and threat-detection response is triggered, it often matters not. The brain takes over and reflexively goes into a tremendously misguided survival mode, which sometimes results in extreme acts of violence.

Fortunately, our forebrain can (and often does) squash these thoughts before they become a problem. This is why, if anyone on the verge of violence allows themselves even a second to stop and think, they often decide against it. The circuits from our forebrains tell the rest of our brain to calm down, and, you know, not kill that person. Unfortunately, many instances of violence are the result of poor impulse control, or they occur under the influence of drugs or alcohol. Poor impulse control, or substances that alter how our brains function, can result in passionate, unpredictable and rash behaviours.

But still, the question remains – What about our morality? The thing is, our morals are personal, and can fluctuate. There’s no definite ‘moral region’ of our brains, and morality is often a combination of complex decision making, empathy, and agency. So, there are lots of factors at play, and our sense of ‘right and wrong’ is far from ‘black and white’.

Our emotions often take a major role in shaping our morality at any given moment, with our brains typically favouring any emotional rise over our moral constant. It can be loosely linked to the famous “footbridge dilemma”, a hypothetical situation wherein a train is about to plow into a group of people. In order to save them, you must push someone you love into the path of the train. Would you do it? Most people say no, as they’re promoting their personal feelings above everything else. And we’re again back to that tribal mentality.

Research has shown that we can essentially “switch off” regions of the brain associated with morality. So, in order to believe a situation justifies the violence we’re on the verge of committing, our brains shut down regions linked with empathy and discomfort. Say someone in your family desperately needs medicine, and someone else is stockpiling it all but refusing to cooperate. If you personally feel like the situation justifies a violent response, your brain could begin to temporarily adapt, to allow you to carry out your mission. A similar search for justification takes place in all types of scenario, from a fist-fight between strangers to the bombing of cities during warfare. And in some cases, after a variety of variables are in some way satisfied, human beings end up killing other human beings.

Why do we, as a species, kill each other more than other mammals? Perhaps it’s the product of primal biological programming. Maybe it’s the complex emotions we feel compared to other animals. We’re territorial, tribal, and impulsive, all of which makes us potentially volatile, unpredictable, vengeful or driven by destructive attitudes of hate. And while most people do act upon their conscience, exactly what that is differs from person to person. Essentially, there’s no one reason why humans continually kill each other, which is perhaps the most frightening and disheartening thing of all.