Some of the world's nastiest behavior grows out of spite, the dark art of hurting an opponent even when it comes at a price to yourself.
Divorcing couples often go out of their way to hurt each other and even their kids, skirting the more peaceful path to moving on.
Tax evaders can grow so vengeful over a penalty that they'll double down on their cheating.
Terrorists can be so keen to hurt their enemies, they commit suicide in the process.
Spitefulness can even elevate a small slight, like lurking in wait for a parking space, into a vengeance worthy transgression.
"There are those tiny, little instances of spite that probably happen on a day-to-day basis," said David Marcus, a Washington State University professor of psychology. "There were actually some researchers who did some parking lot research a while back and found people take longer leaving a space when they see someone waiting for the spot."
Test measures spitefulness
In spite of spite's large and small impacts, and the obvious power it can hold on the human psyche, it has been "virtually ignored" by social, personality and clinical psychologists, Marcus said in a recent paper, "The Psychology of Spite and the Measurement of Spitefulness," in the journal Psychological Assessment. Along with graduate student Alyssa Norris and colleagues at Oakland University and the University of British Columbia, he has attempted to remedy that oversight by measuring spitefulness with a test similar to those used for other personality traits.
In general, spite differs from aggression, which can be exercised at little risk to an aggressor. Spite carries a cost, as if one were calculating that a loss is worthwhile if it takes a toll on one's opponent as well.
Behavioral economists have explored this with ultimatum games in which one player gets to divide a set amount of money in whatever way he or she wishes and if the other recipient rejects the offer, no one gets anything. A purely self-interested recipient will take even the small sum. Money is money, no matter the amount. But some players will turn it down out of spite.
Aligns with other negative traits
To develop a "spitefulness scale," Marcus and his colleagues surveyed more than 1,200 people at two universities and through an online system that drew older participants. Their spitefulness was graded on how much they agreed with 17 scenarios, like, "If my neighbor complained that I was playing my music too loud, then I might turn up the music even louder just to irritate him or her, even if it meant I could get fined," and, "I would rather no one get extra credit in a class if it meant that others would receive more credit than me."
Participants were also surveyed with a variety of other personality tests measuring traits like aggression, psychopathy, narcissism, self-consciousness, self-esteem and Machiavellianism, the willingness to be manipulative and deceitful.
As with other personality traits, said Marcus, spitefulness occurred to varying degrees among the survey participants. And to a certain extent, he said, it lined up pretty consistently with other personality traits one might think would be prone to spitefulness.
It was greatest among people high in psychopathy, who are particularly callous, unsympathetic and unemotional.
"Some people call it 'meanness,'" Marcus said.
Rounding out the "dark triad" of negative personality traits, spitefulness was also greater in people who scored high in narcissism and Machiavellianism.
Future focus: Relational behavior
People with higher levels of guilt, which is a concern for other people and a fear of violating social norms, scored lower on spitefulness, while shame, which is more a sense of inadequacy and failing, scored higher.
Men tended to be more spiteful, possibly because they also tend to score higher on the dark triad traits, said Marcus. But he also wonders if he and his colleagues used more "male spiteful" scenarios than the types of relationship-focused situations that women might be more prone to focus on.
"One item that we may want to look at in the future," said Marcus, "is something like, 'After a bad breakup, do you then go out and sleep with the person's friend even though you're not attracted to that person.' That would be classic relational spiteful behavior."
Kids, elders less spiteful
There were a few bright spots.
In an extensive search of the scholarly literature, Marcus saw research that found children will pick up on an injustice that often prompts spite, but won't necessarily react spitefully.
Like adults, they will reject unfair offers in ultimatum games, "but they'll also reject unfair offers that are in their favor," he said. "It's like at a very early age, for the kids it's all about the fairness. So if they divide up candy and they get more candy than the kids they're playing against, they're like, 'Nope, neither of us is going to get anything.'"
In his own research, Marcus found older people were less spiteful than younger people.