A couple of weeks ago, we blogged about how to create killer landing pages that convert visitors into new customers. We listed some tried-and-true elements that seasoned copywriters have used for decades (in sales letters and then later in landing pages) to drive engagement and boost sales. One of them was to use “liberal amounts of text formatting, esp. bold, italics and ALL CAPS.”

We’ll say it again: use liberal amounts of text formatting, esp. bold, italics and ALL CAPS.

Maybe you’re skeptical that something as simple as text formatting can make you more persuasive. Well, don’t take it from us. Take it from Science. In 1969, the psychologist Robert Zajonc published an article summarizing his experiments in how people react to the presentation of words. After showing his subjects an assortment of made-up words—kardirga, saricik, biwonjni, for example—Zajonc found that people attribute positive connotations to words that are repeated more frequently and set in boldfaced type. Zajonc dubbed this phenomenon the mere exposure effect.

Zajonc’s research has seen renewed popularity recently with the publication of Daniel Kahneman’s new book, Thinking, Fast and Slow. (Nobel-winner Kahneman was one of the first economists to look at economic phenomena through the lens of human psychology, creating the field known as behavioral economics.) Here’s an excerpt from Slate.com’s review of Kahneman’s new book:

Psychologists have devised other ways to make a message more persuasive. “You should first maximize legibility,” says Daniel Kahneman, who describes the Zajonc experiment in Thinking, Fast and Slow, a compendium of his thought and work. Faced with two false statements, side-by-side, he explains, readers are more likely to believe the one that’s typed out in boldface. More advice: “Do not use complex language where simpler language will do,” and “in addition to making your message simple, try to make it memorable.” These factors combine to produce a feeling of “cognitive ease” that lulls our vigilant, more rational selves into a stupor. It’s an old story, and one that’s been told many times before. It even has a name: Psychologists call it the illusion of truth.

Faced with two false statements, side-by-side, readers are more likely to believe the one that’s typed out in boldface. (See what I did there? I used repetition as a rhetorical device.)

Now look, I’m not suggesting that you pack your landing pages or whatever with false statements and baseless hyperbole. That would unethical. But I am suggesting that you use text formatting to reinforce your messaging and bolster your argument. That would be smart.

Read more: The Effect Effect | Slate.com