How your beliefs shape what you can achieve
Below, Nir Eyal shares five key insights from his new book, Beyond Belief: The Science-Backed Way to Stop Limiting Yourself and Achieve Breakthrough Results.
Eyal is a best-selling author, former Stanford lecturer, and one of the world’s foremost experts on behavioral design. His previous books, Hooked and Indistractable, have sold more than a million copies and been translated into 30-plus languages.
Next Big Idea Club readers can get an exclusive free download of Eyal’s 5-Minute Belief Change Guide at: NirAndFar.com/beyond-belief-live/.
What’s the big idea?
The best beliefs are both practical and provisional. They offer just enough certainty to act, yet enough flexibility to adapt when new evidence arrives. Choosing your beliefs wisely may be the most important skill nobody ever taught you.
Listen to the audio version of this Book Bite—read by Eyal himself—in the Next Big Idea app, or buy the book.
1. Beliefs are tools, not truths.
Most people picture motivation as a straight line: If you want the benefit, then you’ll do the behavior. You do the work; you get the reward. Simple cause and effect. But this model is incomplete.
Knowing what to do and why you should do it isn’t enough. If it were, we’d all follow through on everything we know is good for us. You can have a perfect plan, backed by solid reasoning, but if you don’t believe your effort will make a difference, you won’t persist. And without that belief, even the best advice becomes wasted breath.
I learned this the hard way through 30 years of failed diets. Every plan worked until it didn’t. Every approach succeeded until I abandoned it. The pattern wasn’t about calories or carbs. It was about belief. When I truly believed in a diet, I followed it with near-religious devotion. But the moment doubt crept in, the commitment collapsed.
In the 1950s, biologist Curt Richter discovered something remarkable about rats swimming in glass cylinders. The ones who gave up and drowned weren’t physically weaker than those who survived. The difference was entirely in their minds. With one simple intervention, Richter transformed how long these animals could persist by a factor that still astonishes researchers today. I explain what that intervention was in the book.
The real question isn’t Is this belief true? but rather Does this belief serve me? Like a carpenter choosing between a hammer and a saw, we can select beliefs based on how well they serve our goals. Beliefs are tools, not necessarily truths.
2. You don’t have relationship problems; you have perception problems.
Think about the last time you had a heated argument with your partner, perhaps over something as mundane as household chores. You go to get a glass of water, and your spouse says, “All the glasses are in the sink.” You perceive their tone as accusatory. Within minutes, you’re in a full-blown argument. Meanwhile, your partner is genuinely confused by your defensive reaction, believing they simply made a neutral statement of fact.
Despite experiencing the same 30-second interaction, the same words, the same environment, you each walk away with entirely different perceptions of what happened. You’re sure they were attacking you. They’re equally sure they were just stating an observation. Neither of you is lying nor deliberately misinterpreting. Your differing beliefs about each other’s intentions created two versions of the same reality.
Your conscious mind can process only about 50 bits of information per second. But your senses are collecting 11 million bits at that same moment. We live life through a keyhole of attention. Your brain fills in the gaps with beliefs, essentially hallucinating much of what you think you’re experiencing.
This is why two people witnessing the exact same event walk away with entirely different experiences. And it’s why the path to better relationships isn’t just better communication skills. It starts with examining the beliefs that shape what you see and hear in the first place.
3. Lies can become reality.
When Serena Williams was preparing for Wimbledon, she found herself trapped in a cycle of self-limiting beliefs. Her nerves were affecting her play at the net, causing her to hesitate. With only two weeks before the tournament, her coach, Patrick Mouratoglou, made a bold decision. He told her that the statistics showed she was winning 80% of points at the net.
It wasn’t true. Not even close. But from that day forward, her performance transformed. She approached the net more frequently and more confidently. Her physical play underwent a dramatic change. As Mouratoglou later confessed, “The lie became the reality.” Williams went on to win the tournament.
This pattern appears consistently in research on performance. In one study, men who believed they were taking performance-enhancing steroids gained significantly more strength than a control group, even though the pills contained nothing but sugar. Their belief didn’t just make them feel stronger. It made them actually lift heavier weights because they trained with greater intensity and pushed harder.
Your expectations shape your effort, and your effort shapes your outcomes. This applies whether you’re negotiating a salary, building a business, or asking for the sale. The research shows that what you anticipate has measurable effects on what you achieve. The question is: What beliefs are you carrying into your most important moments? And are they helping you or holding you back?
4. Your beliefs can become your biology.
What if your thoughts could influence not just how you feel, but how long you live? Researchers have found that people seem able to postpone death until symbolically meaningful occasions. When three American presidents all died on July Fourth, it suggested something profound about the connection between mind and body. But the science goes far deeper than historical coincidence.
In rigorous studies, researchers discovered that beliefs about aging predict longevity better than cholesterol levels, blood pressure, or whether someone smokes. People who held positive views about getting older lived, on average, seven and a half years longer than those with negative views. That’s a bigger effect than you’d get from exercising regularly!
Now, the field of mind-body research is filled with exaggerated claims and studies that don’t hold up. I spent considerable time separating wishful thinking from real science. Some famous studies you may have heard about, like elderly men “thinking themselves younger” or hotel cleaners losing weight just by viewing their work as exercise, haven’t replicated well under scrutiny.
But the research that does hold up is remarkable. Your beliefs trigger real physiological changes through specific, measurable pathways. The key is understanding which mental interventions work and which are nice stories that crumble under scientific rigor.
5. Helplessness is your default. Hope must be learned.
In the late 1960s, researchers Martin Seligman and Steven Maier conducted famous experiments showing that animals who experienced uncontrollable negative events eventually stopped trying to escape, even when escape became possible. They called this “learned helplessness,” and the concept transformed our understanding of depression, trauma, and resilience.
But a detail buried in their data haunted the researchers for decades. Some animals never gave up, no matter what. Only with modern brain imaging technology did Maier discover the stunning truth: The brain’s first response to difficulty is always to freeze. What appears to be learned helplessness is actually the brain’s default state. The animals who kept trying had learned something that overrode this default. They had learned hope.
Think about what this means for your own life. Those moments when you feel stuck, procrastinating on an important project, delaying a difficult conversation, hesitating to make a career change, aren’t evidence of personal weakness. They’re your brain’s ancient operating system doing exactly what it evolved to do.
But here’s the liberating part: If hope is learned, it can be taught. There are specific experiences that build what researchers call the “hope circuit” in your brain. Each time you prove to yourself that your actions matter, you’re not just solving a problem. You’re rewiring your capacity to persist through the next challenge. The question is how to create those experiences systematically.
We all face the same fundamental challenges: building meaningful relationships, creating financial security, maintaining our health as we age, and finding the motivation to pursue what matters most. Research reveals that our beliefs underlie all these outcomes. Not as magical thinking or empty affirmations, but as practical tools that shape what we notice, what we feel, and what we do.
Enjoy our full library of Book Bites—read by the authors!—in the Next Big Idea app.
This article originally appeared in Next Big Idea Club magazine and is reprinted with permission.