We started with books. Analyzing around a quarter of a million Amazon book reviews revealed that present tense increased impact. Saying a book “is” rather than “was” a good read or “has” rather than “had” great plot development led other people to find a review more helpful.

Said another way, present tense suggests that speakers don’t just have an opinion, they are relatively certain about it.

Indeed, when we analyzed the movies, we found that those which interspersed highly positive moments with strongly negative ones were more successful. Movies that repeatedly traversed from the lowest of emotional lows to the highest of emotional highs, and back again, were liked more.

Restaurants with more emotional reviews get more reservations, movies with more emotional reviews do better at the box office, and books with more emotional reviews sell more copies. Using emotional language suggests people have stronger attitudes, which may lead their experiences to have a bigger effect on others.

But rather than always being persuasive, whether emotional language encourages action depends on is the type of thing we’re trying to persuade people about.

The more emotional language an article used, the more likely audiences were to keep reading.