(CNN) "I think therefore I am," mind over matter, the little engine that thought he could -- our philosophers, language and literature all point to the power of perspective.
Psychologists say this common wisdom is right: What you expect from yourself and the world make a big impact on the results of your endeavors.
"From a neuroscience perspective, the brain will believe anything you tell it, right and wrong," said Roseann Capanna-Hodge, a psychologist based in Connecticut.
Research has shown that this phenomenon can have huge benefits when approaching a significant or difficult task, said David Robson, science writer and author of "The Expectation Effect: How Your Mindset Can Change Your World."
"We do know that there's the mind-body connection, which isn't kind of mysterious or magical, it's just, it's how it has to work and that this is in itself changing our physiology," Robson told CNN Chief Medical Correspondent Dr. Sanjay Gupta in his podcast, Chasing Life.
Thinking that you could catch up in a race or that your public speaking anxiety could help you perform better does, in many cases, Robson said.
Psychologists agree and say that rerouting your expectations to work more for you takes self-awareness, self-compassion and resilience. Here are six expert ways to develop a mindset that pushes you toward success.
Expectations, even negative ones, are meant to help our brains navigate a complicated world by simplifying our predictions of the wide range of outcomes to any situation, Emiliana Simon-Thomas, science director of the Greater Good Science Center at the University of California, Berkeley, said.
Those negative expectations can help up anticipate and avoid danger, but they aren't always up to date with the context that surrounds us, she added. The bias to sense danger sometimes inaccurately skews how we see the situation ahead of us.
And inaccurate information in the face of a challenge can create obstacles of its own.
"Pessimistic thoughts really just put you in a position where you're more vulnerable to actually experiencing that unpleasant or negative outcome," she added.
Setting more positive expectations -- and hopefully reaping the rewards -- starts with how you talk to yourself, Capanna-Hodge said.
When baseball players step up to the plate, they tell themselves they will knock it out of the park, she said, and the rest of the world should be doing the same, whether it comes to dietary changes, dating, career development or physical challenges.
Sometimes, though, those negative thoughts feel pretty automatic. If that's the case, Capanna-Hodge recommends activities like prayer, meditation, journaling and visualization to get better in touch with your goals and more in control about how you think about them.
We tend to see ourselves and our obstacles in two ways, Simon-Thomas said. Either our abilities are fixed or can grow, and our obstacles are a threat or a challenge.
Shifting focus to believe that we can develop skills and to see difficulties as a challenge to be met rather than a threat to be avoided has shown to result in more success, she said.
"Is this a challenge that I can get excited about trying to drum up the resources to accomplish? Or is this a threat to my worth as a person?" Simon-Thomas said. "If you could relate to or interpret that situation as a challenge, your physiological response is empowering and equips you to be more creative and effective."
An optimistic expectation doesn't always mean tying yourself to one specific outcome, said Joan Rosenberg, a California-based psychologist and author of "90 Seconds to a Life You Love: How to Master Your Difficult Feelings to Cultivate Lasting Confidence, Resilience, and Authenticity."
Instead, she recommends setting expectations that anticipates a positive result, without being too hard on yourself.
For trying something new and challenging, Rosenberg said her ideal mindset is "I'm going to do the best I can and see just how far I can stretch."
The disappointing truth is those seeking to accomplish something new often will have to fail at least a few times. Part of going into those challenges with an optimal mindset means preparing to face whatever the emotional consequences are -- win or lose.
It usually isn't the loss people avoid, but the feelings that can come with it, like fear, anger, vulnerability, sadness and embarrassment, Rosenberg said. For most, the worst part are the physical feelings that come with a setback, like a flush in your cheeks or racing heart.
Fortunately, data has showns those feels tend to last for no more than 90 seconds, she added. Preparing yourself to sit through whatever unpleasant emotion and feeling may arise can make you more ready to charge into the challenge as well as more resilient if it doesn't go your way, she said.
Sitting in those uncomfortable feels of loss can actually be turned into a gain, Rosenberg added.
She recommended people find the opportunity to find information in the disappointment. Perhaps you learn that you need to eat something more substantial before your 5K or triathlon, that your feelings of sadness mean you really care about the kind of job you were interviewing for, or that the new friends you have been spending time with don't make you feel that good.
"Why would I want to stay present in those feelings? Because it's a source of information that when, joined with thought and reason, will help me make better decisions in my life," Rosenberg said.
Having realistically optimistic expectations is not a cure-all for life's disappointments and losses, but it does better equip each of us to go into a challenge with our best resources, experts said.