Working towards a 'neuroscience of human evil', psychological scientists Martin Reimann and Philip Zimbardo came up with a different idea as to why we are capable of horrible acts. In their 2011 paper, 'The Dark Side of Social Encounters,' the authors try to establish what parts of the brain are responsible for evil. They state that two processes are most important—deindividuation and dehumanisation. Deindividuation happens when we perceive ourselves as anonymous. Dehumanisation is when we stop seeing others as human beings, and see them as less than human. The authors also explain dehumanisation as a 'cortical cataract,' a blurring of our perception. We stop being able to really ee people.
This is apparent when we talk about 'the bad guys.' The statement dehumanises. It assumes that there is some homogenous group of individuals who are 'bad,' and who are different from us. In this dichotomy, we, of course, are 'the good guys'—a diverse group of human beings who make ethically sound decisions. This dividing of the world into good guys and bad guys was one of Hitler's preferred approaches. Even more distressing was the development of the argument that those targeted were not even made up of 'bad people', that they were not even human. A dramatic example of dehumanising was seen in Hitler's genocidal propaganda, where he described Jewish people as untermenschen—subhumans. The Nazis also compared other groups they targeted to animals, insects and diseases.
More recently, the United Kingdom and United States have seen a string of vitriolic public statements about immigrants. In 2015, British media personality Katie Hopkins described migrants arriving in boats as 'cockroaches', a term that was publicly criticised by the UN's human-rights chief, Zeid Ra'ad Al Hussein. He retorted, saying,'The Nazi media described people their masters wanted to eliminate as rats and cockroaches.' He added that such language was typical of 'decades of sustained and unrestrained anti-foreigner abuse, misinformation and distortion'. Similarly, on 1 May 2017, the 100th day of his presidency, Donald Trump read aloud as part of a speech the lyrics of a song about a snake originally written in 1963 by Oscar Brown Jr.
On her way to work one morning
Down the path alongside the lake
A tender-hearted woman saw a poor half-frozen snake.
His pretty colored skin had been all frosted with the dew.
'Oh well,' she cried, 'I'll take you in and I'll take care of you.'
. . .
Now she clutched him to her bosom, 'You're so beautiful,' she cried,
'But if I hadn't brought you in by now you might have died.'
Now she stroked his pretty skin and then she kissed and held him tight
But instead of saying thanks, that snake gave her a vicious bite.
Trump uses the story as an allegory about the dangers of refugees. He is comparing refugees to snakes.
This kind of oversimplified grouping of an imagined enemy is echoed over and over in politics, partly because it is so catchy. With a bit of help from a leader and some inspiring rhetoric, harmful ideologies readily flourish. And, while we all sometimes fall into this trap, some of us are particularly prone to being influenced by such poisonous imagery.
This is where we really begin our imagined reconstruction of Hitler's brain. Given his particular propensity for dehumanising, the parts of the brain responsible for this may have been particularly affected. According to Reimann and Zimbardo, deindividuating and dehumanising 'could potentially involve a network of brain areas, including the ventromedial prefrontal cortex, the amygdala, and brainstem structures (i.e., hypothalamus and periaqueductal gray)'. Helpfully, they provide an image of their model, which I have reconstructed for you. (FIGURE NOT SHOWN)
Their model suggests that what starts as a feeling of anonymity, of not being to blame for what we do because we feel like we are simply part of a larger group, ends with an increased ability to do harm to others. Here's how they propose evil works in the brain.
Deindividuation. The person stops thinking of themselves as an individual, and identifies as an anonymous part of a group. This leads them to feeling like they are not personally accountable for their behaviour. This is related to a decrease in the activity of the ventromedial prefrontal cortex—vmPFC. Reducing the activity in the vmPFC is known to be linked with aggression and poor decision-making, and can lead to disinhibited and antisocial behaviour.
Dehumanisation This decreased activity is accompanied by an increase in activity in the amygdala, the emotion part of the brain. This is linked to feelings such as anger and fear.
Antisocial behaviour. Then, these experienced emotions go via the brainstem to trigger other sensations, like increased heart rate, blood pressure and gut feelings. These changes are essentially the body getting into fight-or-flight mode—anticipating bodily harm and getting ready to survive.