On television and on the stump, at debates and in speeches, Donald Trump is reminding the American people that they are going to die. The reminders aren't explicit, and they probably aren't part of an intentional strategy. All the same, much of Trump's rhetoric could have the effect of bringing his viewers' omnipresent fear of death closer to their conscious minds, according to Sheldon Solomon, a psychologist at Skidmore College in Saratoga Springs, New York.
That includes his emphasis on terrorism, unsurprisingly, but also his preoccupation with immigration.
This focus might be helping Trump, since Solomon's recent research shows that people who are thinking about death are more likely to say they support him.
Study subjects who were prompted to talk about their own death later rated their support for Trump 1.66 points higher on a five-point scale than those who were prompted to talk about pain generally.
"I'm not suggesting that any of this is calculated, but almost everything that he does is demonstrably effective for raising these non-conscious, existential concerns that in turn make his kind of candidacy all the more alluring," Solomon said.
Solomon is part of a group of researchers that has spent decades investigating the connections between death and a broad variety of human beliefs and behaviour.
Their inspiration has been the work of Ernest Becker, an anthropologist who argued that the fear of death was a kind of fundamental principle in explaining human psychology.
Becker won a Pulitzer Prize for his 1973 book The Denial of Death, but he was shunned in the academic community for what his peers saw as a lack of rigor.
"It was existential, psychodynamic, philosophical speculation for which there was no empirical proof," Solomon said. He and his colleagues have tried to supply that proof through experimentation.
Their research is still preliminary and controversial, and they haven't worked out a complete theory, but they have discovered a number of startling facts about how people think about death.
For example, Solomon and Florette Cohen of the City University of New York, College of Staten Island recently found evidence that asking people to think about immigrants also gets them thinking about death.
Solomon and Cohen asked a small group of volunteers at the College of Staten Island to respond to one of three prompts.
One group was asked to write down what they thought would happen, in as much detail as possible, if immigrants moved into their neighbourhoods, and what emotions they would feel.
The other two groups were asked to answer the same questions, but about their own deaths and about feeling intense pain instead of about immigration.
Then the two researchers gave the participants a set of words with letters missing and asked them to fill in the blanks to get an idea of what the participants were thinking about.
Shown "C O F F _ _," for example, many people might write "COFFEE," especially students in college. If they were thinking about death, however, they might write "COFFIN" instead.
The participants who had been asked to think about immigration had death on their minds, too - almost to the same extent as those who had been asked to think about death explicitly.
Assigned scores from zero to one based on how many words related to death they produced, those who had been asked to think about immigration scored 0.92 on average, while those who had been asked to think about death scored 0.96.
Those asked to think about pain scored just 0.19. There was no evidence that the effect was greater for conservative participants in the study.
Solomon said he hopes to replicate the study, which was completed with a small group of a few dozen students at the College of Staten Island.
Yet the results accord with those of similar studies that suggest people interpret challenges to their culture as threats to their very existence.
A different group of researchers found that after a group of Canadians read an article in which Canadian cultural tropes were mocked, they were thinking about death, too.
The pattern extends to religious beliefs. Another study found a comparable effect in atheists confronted with arguments in favour of intelligent design, and a third concluded that pointing out logical inconsistencies in the Bible made thoughts of death also more accessible to fundamentalist Christians.
For Solomon, the research suggests that when people create meaning in their lives - whether through religion, nationality or "staying at home with a 30-pack of beer and spraying some Cheez Whiz on a cracker," in Solomon's words - they are protecting themselves from their constant awareness of death.
He and his colleagues have argued that the same is true of clothing and grooming, and that humans conceal their nature as animals from themselves to avoid thinking about their mortality.
Solomon and his colleagues also have found that thinking about death makes charismatic, resolute leaders more appealing.
They showed that to be true during President George W. Bush's successful campaign for reelection against John F. Kerry, now the secretary of state, in 2004, and Solomon's new research with Cohen has produced similar results for Trump.
They rated participants' support for Trump on a scale out of five points based on their answers to several questions.
The average rating for those who had been reminded of their mortality was 3.8 points, but it was just 2.2 points for those who had been asked to think about pain.
Solomon said these results suggest that the fear of death is one of several interrelated psychological concepts that could help explain why Trump has been so successful, including authoritarianism, an aversion to uncertainty and racial prejudice.
"It sure seems like an existentially shaky historical moment where it has become increasingly difficult for the average American to perceive that they have any basis for either meaning or self-worth," Solomon said.
"It is a factor, and in a very close election, it could matter."