In tough times, people want more in a leader than intelligence, integrity, or the ability to build really tall walls. They want someone who can make a compelling pitch and inspire a sense of urgency—someone with charisma. For decades, scholars have struggled to define this X factor, but they are developing a better idea of how it works.

According to an evolutionary theory proposed by a pair of psychologists, charisma is the ability to convince followers that you can get other members of a wider group to cooperate. These researchers found that exposure to charisma increased generosity: Subjects who saw a ted talk by a charismatic speaker later gave more money to a stranger than did those who saw an uncharismatic one. And thinking about a charismatic person (versus an acquaintance) made people more likely to cooperate with a stranger. [1]

We’re most swayed by charisma when lacking data on a leader’s record. In one study, subjects had to decide whether to keep or boot a CEO after watching a fake newscast describing him as high or low in charisma and his company’s stock price as rising, sinking, or relatively flat. Charisma helped the CEO most when performance was ambiguous. The researchers also rated past presidential candidates’ charisma, by combing their speeches for charismatic tactics—storytelling, expressing moral conviction, setting high goals. Only when economic indicators were muddled was charisma strongly correlated with votes received. [2]