There are two types of people in the world: those who dream and those who do. What sets them apart?

What sets apart the student who perseveres from the one who decides education isn't really for her? What makes one person get up at 5 a.m. every day to squeeze in a run while another person just berates himself for his laziness from the comfort of his couch? What separates the professional with stalled entrepreneurial dreams from the founder slogging her way through the startup trenches?

You might think that the answer to each of these questions is different--the failed student might lack intellectual ability, or maybe the successful founder is simply luckier than the wantpreneur--but according to cognitive psychologist Amanda Crowell, those who persevere and achieve their dreams in any domain are actually successful for the same reason--they all share a few essential beliefs.

Every successful person shares these beliefs.

In a compelling and personal post for Quartz, Crowell relates the story of her own efforts to get started with a fitness routine. Like many of us, she struggled to keep her weight down as she got older, and also like many of us, she nonetheless found it incredibly difficult to exercise as much as she knew she should.

But Crowell managed to turn the situation around and recently completed a triathlon and a half marathon. What made the difference? She finally figured out that the insight she needed to get moving was staring her in the face as part of her work. She just needed to connect the dots.

"In my professional life, I work with schools to help struggling students re-engage with academics. One major focus is addressing students' mindsets. According to the Chicago Consortium on School Reform (along with many other educational experts), three concepts influence whether students will persist when things get rough at school," she reports.

What are these three essential beliefs for educational success? Here they are, in Crowell's words:

  1. The belief that hard work can and will lead to improvement.
  2. Confidence that you, and people like you, belong in school and that it is a place where you can thrive.
  3. The belief that what you are doing is valuable and relevant to your goals.

You can change your mindset.

Crowell's eureka moment came when she realized that these three beliefs weren't just a prerequisite for success in school, but were actually required for anyone to achieve his or her goals. If you think exercise is futile, it's no shock that you don't hit the gym. And if you don't really value starting a business, obviously you're not going to stick with the process through the many inevitable ups and downs.

It seems obvious. But actually most motivation problems can be traced to a lack of one or more of those three simple but essential beliefs--you don't really believe you have a shot, you're convinced that people like you don't belong wherever it is you're aspiring to go, or you simply don't really want whatever it is for yourself enough.

Which was just what was holding Crowell back from getting fit. She didn't believe she could succeed, didn't see herself as a "gym person," and didn't truly value exercise. "In order to change, I used a series of techniques that are actually applicable to any number of areas--from becoming a better student to learning how to play a musical instrument," she explains before outlining the steps she took to shift her mindset.

If you're also struggling to stick with your dreams, it's well worth reading about her journey in greater detail. But first, you need to honestly evaluate your own mindset: Do you truly, deeply believe the three things that underlie all success?