In 2016, Donald Trump promised to "build a wall" between the US and Mexico, and to bring back jobs to the American people. In the UK, Nigel Farage ran a campaign saying the country had reached a "breaking point" with immigrants, and Britain had to leave the EU to fix it.
Some of the statements made by nationalistic parties over the world regarding immigration are based in truth and some are false. But what is clear is that immigration has become a buzzword that whips people up into a frenzy of anger and resentment.
Rather than seeing immigration as a positive for the economy, for some it has become a scapegoat for all of their nation's problems. And according to a new study from the University of Cambridge's Conspiracy & Democracy project, around a third of people in several countries think their governments are making things worse, and "hiding the truth" about immigration.
The study was based on YouGov survey data from nine countries: the US, Britain, Poland, Italy, France, Germany, Portugal, Sweden, and Hungary.
One of the major findings was that voting for Brexit or Donald Trump was associated with believing conspiracy theories, from climate change denial to the amount of Muslim migrants in the country.
Project researcher Hugo Leal said anti-immigration conspiracy theories have spread and gained ground since the refugee crisis happened in 2015.
"The conspiratorial perception that governments are deliberately hiding the truth about levels of migration appears to be backed by a considerable portion of the population across much of Europe and the United States," he said.
About 11,500 people were surveyed in total. The results showed that in Britain, 30% of people believe their government is hiding the truth about immigration, as well as 21% of those in the US.
But that figure rises to nearly half of those who voted Brexit in the UK (47%) and for Trump in the US (44%), compared to 14% of Remain voters and 12% of those who voted for Clinton.
In Hungary, with an anti-migrant prime minister Viktor Orban, 48% of people think the truth is being hidden, while in Germany the figure is 35%, followed by 32% in France and 29% in Sweden.
Also, more nationalistic voters - 41% of Trump voters and 31% of Brexit voters - subscribed to the theory of "the great replacement," which is the idea that there is a plan for Muslims to become the majority of a country's population. This is compared to just 3% of Clinton voters and 6% of Remain voters.
For reference, Islam is the second largest religion in the UK, but Muslims only make up around 4.4% of the total population. In the US, it's even lower at 1.1%.
The team also looked at other conspiracy theories. Both Trump and Brexit voters were more likely to believe climate change is a hoax, vaccines cause harm, and there is a secret society of people secretly controlling the world (like the Illuminati).
Leal said generally believing these sorts of conspiracy theories linked both electorates, and the level of science denial is an "alarming global trend."
Hugo Drochon, another researcher at the Conspiracy & Democracy project, said rising beliefs in conspiracies can have an impact on public policy.
"We tend to think of conspiracy theorists as isolated individuals who will become convinced you must be 'part of the plot' if you try and dissuade them of their beliefs, but there are structural issues at play here too," he said.
"We found countries that are more unequal and have lower quality of democratic life tend to display higher levels of conspiracy belief, which suggests that conspiracy belief can also be addressed at a more 'macro' societal level as well."
When looking at conspiracy skepticism, Sweden came out on top, with 48% of people rejecting every conspiracy they heard. The UK followed with 40%. Hungary was the lowest with just 15% not believing any.
In all countries except Germany, about half of respondents said they got their news from social media - usually Facebook or YouTube. Overall, receiving news from social media was less associated with skepticism, and YouTube was particularly connected with adopting anti-vaccine and climate change denial beliefs.
In 2017, a study published in the European Journal of Social Psychology found that some people like believing in conspiracy theories because they want to be original.
Researchers assessed 238 people for their need for uniqueness, and their endorsement of 99 conspiracy theories. The results showed that believing one conspiracy theory makes it more likely you'll believe another, and that there was a correlation between this endorsement and the need to not follow the crowd.
The authors concluded that the results highlighted a neglected function of conspiracy theories: to present oneself as distinct from the crowd.
"All humans share not only the need to belong and affiliate with others but also to be different and stick out from them, to be an identifiably unique individual," they wrote.
In other words, if we are seen as the conspiracy theorist, we might not be regarded as always correct, but we will probably be remembered.
There's arguably something else going on when it comes to subjects like immigration. Often, real concerns of people like unemployment, cheap labour, and declining benefits cause people to place the blame on something tangible, like the foreign families who moved into their small town.
In a blog post for Psychology Today, psychologist Arash Emamzadeh highlights several reasons for hostility towards immigrants. For example, false negative stereotypes that immigrants are lazy, commit crimes, are more likely to live in poverty and depend on welfare, and refuse to learn the country's language.
There's also the perceived threat of "the other" - people who have different cultural beliefs and behaviours they don't understand. And the fact people from other countries may be working for less money, meaning there are fewer jobs than before.
People believe conspiracy theories for a number of different reasons, and this doesn't seem to be changing. As with the anti-vax movement, it's unlikely anti-immigration fears can be tackled with facts and figures alone. For instance, a Pew Research Center analyisis last October found that scientific literacy usually doesn't change a person's views on political matters like climate change.
Rather than spouting numbers, the solution probably lies with getting to the root of the problems people are facing. This is often what causes groups of people to be so open to alternative explanations, whether they are true or not.
This is an undeniably difficult task, but it is more important than ever, as such beliefs no longer lie on the fringe. Conspiracies now play a big part in nation wide policies and elections, giving them further validation.
"A telling takeaway of the study is that conspiracy theories are, nowadays, mainstream rather than marginal beliefs," said Leal. "These findings provide important clues to understanding the popularity of populist and nationalist parties contesting elections across much of the western world."
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