Fake news is everywhere in 2018 - but why we believe it is still unclear.
Psychologists have offered one explanation: that valuing our identity more than our accuracy is what leads us to accept incorrect information that aligns with our chosen political party's beliefs.
That value discrepancy, they believe, can explain why high-quality news sources are no longer enough - and understanding it can help us find better strategies to bridge the political divide.
"Neuroeconomics has started to converge on this understanding of how we calculate value," explained New York University psychologist Jay Van Bavel.
"We're choosing what matters to us and how to engage with the world, whether that's which newspaper we pick up in the morning or what we have for breakfast.
"And so we started to think, it's when our goals to fit in with certain groups are stronger than the goal we have to be accurate that we are more likely to be led astray."
This is what he calls his identity-based model of belief.
The idea is that we assign values to different ideas based on what matters to us most at the moment and then compare those values to decide which idea we believe is true.
Because our political parties can provide us with a sense of belonging and help us define ourselves, agreeing with them can bolster our sense of self.
And that could sometimes matter more to us than accuracy about an issue - even if accuracy was something we normally did care about.
When that happened, we'd likely believe the ideas that aligned with our party's views, no matter how plausible.
This can mean that the sources of information we normally rely on to shape our views have less of an impact.
"Having a really high-quality news source doesn't matter that much if we think the people producing it belong to a different group than us," Van Bavel said.
"They might have the best writers, the best investigative journalists, the best editorial standards, all the stuff that we would normally care about."
But we stop valuing those things that would normally lead to a high likelihood of accuracy, and instead focus on the group we think the news is aligned with.
Still, Van Bavel does believe his model offers strategies that can help bridge the political divide.
"Our model really doesn't pick a side - what it argues for is increasing the value of truth or finding ways to reduce the effects of identity, whether on the left or the right."
Being put into a role that required someone to be accurate, like being summoned for jury duty, could give people criteria with which to evaluate information and help them be better at thinking critically.
Even more simply, Van Bavel said we could increase the value of accurate beliefs by asking people to put their money where their mouth is.
"When you are in a disagreement, ask your opponent, 'You wanna bet?' And then their accuracy motives are increased, and you can see right away whether they were engaging in motivated reasoning," he said.
"Suddenly $20 is on the line, and they don't want to be proven wrong."
We could also work to reduce the effects of identity.
One way was by creating a "superordinate identity" - or getting people to think of themselves as citizens of a nation or the world rather than as members of a political party.
But we also had to pay attention to how we engage with people of different political persuasions.
"It turns out that if you insult them and publicly criticise them, their identity needs increase, and they become threatened and less concerned about accuracy," he said.
"You actually need to affirm their identity before you present information that might be contradictory to what they believe."
In a political climate that brought us Donald Trump, he believed the message was simple.
"Our partisan identities lead us to believe things that are untrue. So, we need to step back and critically evaluate what we believe and why."
Can smell reveal our politics?
Speaking of Trump - does being more sickened by other people's smells make you more likely to support him?
It's an odd link to make, but researchers suggest that people who are easily disgusted by body odours are also drawn to authoritarian political leaders.
A survey showed a strong connection between supporting a society led by a despotic leader and being sensitive to body odours like sweat or urine.
It might come from a deep-seated instinct to avoid infectious diseases.
"There was a solid connection between how strongly someone was disgusted by smells and their desire to have a dictator-like leader who can suppress radical protest movements and ensure that different groups 'stay in their places," said study author Jonas Olofsson, of the University of Stockholm.
"That type of society reduces contact among different groups and, at least in theory, decreases the chance of becoming ill."
Disgust was a basic emotion that helps us survive.
When people were disgusted, they wrinkled their noses and squinted their eyes, basically decreasing their sensory perception of the world.
At its core, disgust was a protection against things that are dangerous and infectious - things that we want to avoid.
The researchers had a theory that there would be a connection between feelings of disgust and how a person would want society to be organised.
They thought people with a strong instinct to distance themselves from unpleasant smells would also prefer a society where different groups were kept separate.
A scale was developed for the participants to rate their levels of disgust for body odours, both their own and others.
This scale was used in a survey given online in different countries, together with questions on political views.
In the US, questions about how they planned to vote in the presidential race in 2016 were added.
"It showed that people who were more disgusted by smells were also more likely to vote for Donald Trump than those who were less sensitive," Olofsson said.
"We thought that was interesting because Donald Trump talks frequently about how different people disgust him.
"He thinks that women are disgusting and that immigrants spread disease and it comes up often in his rhetoric.
"It fits with our hypothesis that his supporters would be more easily disgusted themselves."
The results of the study could be interpreted to suggest that authoritarian political views were innate and difficult to change, but Olofsson believed these could still change, even if deep-seated.
Why a smile isn't always welcome
A smile can put us ease – but not always.
Researchers have demonstrated how a quick grin can actually increase physical stress responses in situations where we're being evaluated – like a job interview - depending on what we perceive that smile to mean.
Psychology studies have already shown how bad remarks from others - like "that wasn't good" - in everyday scenarios where we're being tested can activate what's called the hypothalamic-pituitary adrenal (HPA) axis, otherwise known as our body's central stress response system.
Until now, little has been known about how we respond to unspoken cues.
US researchers have found that seeing smiles that are rewarding or acknowledging can lower our levels of stress hormones.
But seeing "dominating" smiles - which are actually creepy and signal disapproval - can push up our stress hormone levels.
Participants in the study who perceived these "dominance" smiles took longer to return to their baseline cortisol levels after the stressful situation was over – a response that was quite similar to getting spoken negative feedback.
The authors, from the University of Wisconsin, also found that individuals with higher heart-rate variability – the variation in the time between each heart beat – showed more nuanced responses to different smiles.
They now want to look at whether men and women respond differently to the same kind of smile, and test the physiological effects of those more overtly negative facial expressions.