In order to hack into the minds of the public, people need to feel fear or uncertainty. That could be caused by economic instability or pre-existing cultural prejudices, but the emotional basis is fear. The brain is designed to respond to fear in various ways, with its own in-built defense mechanisms which produce chemicals in the response pattern, such as cortisol and adrenaline. These chemical responses, which zip straight past our logical brains to our fight-or-flight reactions, are also activated by forms of language that instill fear, either directly (as in a vocal threat) or, more insidiously, by twisted facts which allay fears through lies and deceptive statements.

The same is true of conspiracy theories. The neuroscientific research shows that people who believe them develop more rigid neural pathways, meaning they find it difficult to rethink situations once this pattern of thinking is established.

This also means that if someone is already more susceptible to believing lies in the form of dehumanizing metaphors and this same person comes across a big lie or a conspiracy theory that fits into that well-trodden neural pathway, they are more likely to believe it and be influenced by it.

This is how language that might seem like harmless hyperbole winds up literally changing the way people think. And once they think differently, they can act in ways that they might not have before.

With the rise of populist and far-right political movements in the 2010s, the use of dehumanizing metaphors to engender hatred of foreigners or of those who are different in some way has spread worldwide.

Not all hope is lost, however. History has shown that disruptive events - such as the toppling of a regime or the loss of a war - can force a new perspective and the brain is able to recalibrate. So it is at least possible to change this pattern. Once the critical mind is engaged, away from the frenzy of fear and manipulation, the lie can become clear. This is the uplifting moral tale that can be gleaned from history - all the great liars, from dictators to autocrats, were eventually defeated by truth, which eventually will win out.

But the bad news is that you need that kind of disruption. Without these jarring events to bring a dose of reality, it is unlikely that people with strong convictions will ever change their minds - something that benefits the autocrat and endangers their society.