When things get tough, many people turn to a motivational quote for a bit of inspiration. Some of these pithy sayings have become celebrated parts of society’s lexicon. Some include:

“I have not failed. I’ve just found 10,000 ways that won’t work.” —Thomas Edison

“No one can make you feel inferior without your consent.” —Eleanor Roosevelt

“If you can’t fly then run, if you can’t run then walk, if you can’t walk then crawl, but whatever you do you have to keep moving forward.” —Rev. Martin Luther King, Jr.

But out of all of the things that people—famous, influential, and otherwise—have to say, what makes some turns of phrase so powerful that they become mantras for generations?

Depending on whom you ask, the appeal appears to lie in a combination of good wordsmithing, motivational psychology, and a measure of self-selection. Obviously, people who tend to feel inspired by motivational quotes are going to find them more resonant than those who don’t find simple phrases and sayings to be particularly meaningful, says psychologist and motivation expert Jonathan Fader, PhD, founder of the Union Square Practice in New York City.

THE COACHING FACTOR

Fader says there’s a self-selection process that narrows the population of people who are drawn to motivational sayings. Beyond that, the message that someone else believes you can achieve what you want to achieve can be a powerful incentive to try harder, he says. If your teacher, coach, or mentor believes you can do something, you’re more likely to do it.

“There’s a little bit of implicit coaching that’s happening when you’re reading it. It’s building that self-efficacy in that kind of dialogue that you’re having with yourself,” Fader says.

THE POWER OF LANGUAGE

There’s also power in the words themselves, says Ward Farnsworth, dean of the University of Texas School of Law and author of Farnsworth’s Classical English Rhetoric. Farnsworth says that people have an “appetite for well-expressed wisdom, motivational or otherwise.”

“Students of Latin see examples of aphorisms from 2,000 years ago, such as ubi concordia, ibi victoria, ‘where there is unity, there is victory.’ Usually, these sayings involve some keen insight put into memorable wording. They are little triumphs of rhetoric, in the old and positive sense of the word,” he says.

The way an idea is expressed can affect judgments about its merit.

Phrasing contributes to effectiveness—for better or worse. Farnsworth points to a 2000 study by cognitive scientists at Lafayette College that found that when people were shown two statements of the same pithy saying, study participants were more likely to say the rhyming aphorism seemed true.

“As O.J. Simpson’s lawyer once said, ‘If the glove doesn’t fit, you must acquit.’ The study shows that the way an idea is expressed can affect judgments about its merit,” he says. A more upbeat and motivational example is, “Whatever the mind of man can conceive and believe, it can achieve,” by Napoleon Hill.

Farnsworth says the details of wording make a difference. While there are many ways to say the same thing, one may be more pleasing and convincing than all the others because of the way words are arranged. For example, parallel construction where two halves of a claim are “attractively balanced” can be effective, he adds.

“An example is the use of parallel construction, so that the two halves of a claim are attractively balanced, such as ‘marry in haste, repent at leisure.’ The reversal of structure, or ‘chiasmus,’ is also attractive—‘ask not what your country can do for you; ask what you can do for your country,’” he says.

Metaphor use can also make a simple idea compelling. When people talking about business say that you should “skate to where the puck is going, not to where it has been”—or when they just talk about “dropping the ball”—they are making implied comparisons to sports. A metaphor usually succeeds by making its subject more visible, or by making it simpler, or by caricaturing it, Farnsworth says. The quote “Everyone is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid” would be far less powerful or evocative if it stopped after the first sentence.

THE PRIMAL ASPECT

Some of their appeal may even be rooted in biology, says media psychology expert and communications consultant Scott Sobel, founder of Media & Communications Strategies, Inc. in Washington, D.C.

“Humans are aspirational. We want to look up to role models and leaders and follow what they ask,” he says. “Leaders and their words–inspirational quotes–affect us on a primal level.”

Words from recognized leaders in business, politics, and the arts may also hold more gravitas because of the assumption that when people are in public positions, they must be accomplished, wise, or otherwise exceptional to have achieved those positions. Those perceptions can make messages from such leaders more powerful.

For people open to their message, well-structured messages that use strong imagery and appeal to our aspirational nature can be meaningful and powerful in changing our thinking and helping us see something in ourselves that we want to change or overcome, Fader says. That’s one of the main reasons they’re passed on for generations.