Almost a century ago, a plucky little blue engine first I-think-I-canned her way up a mountain in an iconic display of self-efficacy's power.

But the term self-efficacy wouldn’t come along for another 50 years or so, when late psychologist Albert Bandura, PhD, a professor of psychology at Stanford University, introduced it to the world in the journal Psychological Review.

Dr. Bandura says self-efficacy is the belief that you’ll be able to successfully execute a behavior that helps produce an outcome you want, like the Little Blue Engine who believed she could pull boxcars stuffed with dolls and toys to the good little boys and girls in the city below.

Research has since demonstrated a strong link between high self-efficacy for a task and whether you actually do it, adding a scientific spin to the moral of the classic children’s story and suggesting all sorts of implications for health and well-being.

Here’s more about what self-efficacy is, how it can affect your health, and what you can do to boost it.

Self-efficacy is “an individual’s subjective perception of his or her capability to perform in a given setting or to attain desired results,” according to the American Psychological Association (APA).

That means self-efficacy is a personal belief about whether you can perform the behaviors that you think you need to perform in order to accomplish the goals you want to accomplish, says James Maddux, PhD, senior scholar at the Center for the Advancement of Well-Being and professor emeritus of psychology at George Mason University in Fairfax, Virginia.

For instance, you could think that eating 3,000 fewer calories each week will likely result in losing around four pounds per month, says Dr. Maddux. Self-efficacy answers the question: Do you believe you’re capable of actually doing it? In this context, if you’re confident you could reduce your calories and shed a few pounds, you’d have high self-efficacy. If you’re not so sure, your self-efficacy for that task would be low.

In one sense, there are as many types of self-efficacy as behaviors needed to accomplish goals, says Maddux. That’s partly why you’ll find research referring to specific kinds of self-efficacy, like a study on exercise self-efficacy in pregnant women, another study on math self-efficacy in children, and a third study on health self-efficacy in childhood cancer survivors. People do a million things every day, and for each of those, you could have high or low self-efficacy, he explains.

But across all of these instances, the idea of self-efficacy actually deals with a single concept, which is always context-dependent, says Maddux, who authored a chapter on self-efficacy measures for the Encyclopedia of Personality and Individual Differences. Self-efficacy always refers to the belief that you can accomplish a given behavior. And all those different types researchers talk about? “They are simply self-efficacy under different conditions,” he says.

When Bandura introduced the idea of self-efficacy in his original paper, he noted four main sources, which are still recognized as some of the main contributors to self-efficacy, says certified mental performance consultant Amber Shipherd, PhD, membership services division head at the Association for Applied Sport Psychology and associate professor and performance psychology program coordinator in the department of health and kinesiology at Texas A&M University in Kingsville.

• Performance Accomplishments Your own past performances and experiences tend to be the most impactful source of self-efficacy information, says Dr. Shipherd.

• Vicarious Experiences Seeing others try difficult things and succeed makes you think you can do it too. You can also use imagery to picture yourself completing a task successfully, adds Shipherd.

• Verbal Persuasion Telling yourself or others that you’re capable can contribute to self-efficacy, says Shipherd.

• Emotional Arousal Bandura says if you feel afraid, that might make you doubt your ability to handle a task. On the flip side, if you’re calmer or less nervous, you’ll be more apt to think you can handle things. Today, sport and exercise psychologists believe that both physical states (like pain or fatigue) and emotional states (like stress and mood) can inform self-efficacy, says Shiperd.

Some research suggests that self-efficacy could be at least partly inherited, including a study that compared the relative similarity of self-efficacy survey results for genetically identical and fraternal twins. Yet that doesn’t mean self-efficacy is something you must be born with to have. “It is absolutely something that someone can learn,” says Shipherd.

Self-efficacy can influence health and well-being in a thousand ways, says Maddux. This is because high self-efficacy for a task does a pretty good job of predicting whether you’ll actually be successful at performing the task, he explains. In turn, those tasks — from what you eat, to what you drink, to whether you smoke — can all influence health and well-being. Here are highlights from the research.

Self-Efficacy Can Promote Emotional Well-Being

Self-efficacy is associated with many positive, helpful emotions, says licensed mental health counselor Monica Leppma, PhD, associate professor of counseling at West Virginia University in Morgantown. She notes that some research has found a link between self-efficacy and resilience, while other studies have found a connection between self-efficacy and optimism. Likewise, a research review found an association between self-efficacy and self-compassion.

Each of these findings makes intuitive sense. A mindset that you’ll be able to do what you need to do to achieve your goals involves a certain degree of hope, tolerance for setbacks, and a sense that even if you fail or make a mistake, you're still okay as a human being, explains Dr. Leppma.

Self-Efficacy Can Buffer Stress, Anxiety, and Depression

Importantly, self-efficacy appears to protect against a number of threats to your mental health, says Leppma. Research has found that self-efficacy has an inverse relationship to depression and anxiety, meaning that people with greater self-efficacy are less likely to say they are depressed or anxious.

Self-efficacy also appears to ease the effects of daily stressors, per research, making you feel like you can better handle life’s demands. It may even help people cope with extraordinary stress and trauma. Research on 9/11 survivors suggests that self-efficacy can affect the course of post-traumatic stress disorder (PTSD) for the better by reducing its severity and how long it persists.

Self-Efficacy Can Support a More Fulfilling Life

High self-efficacy can make it easier to achieve goals that can make up a good life, says Leppma. For instance, a number of studies examine how self-efficacy relates to your professional life. Research on teaching assistants found that higher self-efficacy is connected to greater job satisfaction. The opposite also seems to be true: Lower self-efficacy can make it more challenging to meet your goals by way of experiencing higher professional burnout, according to research.

These benefits add up. People who say they have higher self-efficacy also tend to say they have a higher quality of life overall, research suggests.

Self-Efficacy Can Help You Manage Chronic Diseases

Believing you’ll be able to cope with chronic illness can make it more likely you’ll be able to do just that. A review of the research on people with essential hypertension suggests that higher self-efficacy is linked to better self-management of the condition, including a greater likelihood of taking prescription medication, staying active, and eating a healthy diet.

Another study on Black women with systemic lupus found that those who reported higher self-efficacy for symptom management and treatment also seemed to have better control over their disease (saying they had less fatigue and less pain) than women with lower self-efficacy.

Self-Efficacy May Help You Make Healthier Choices

Self-efficacy can impact your decision to start and stick with healthy habits, explains Shipherd. In one related study involving 100 Hispanic participants, researchers found that self-efficacy for eating fruits and vegetables and weekly exercise was connected to whether people actually consumed more produce and worked out. Other research has found that people who have quit smoking and had greater self-efficacy were less likely to relapse.

To build self-efficacy, you can draw inspiration from Bandura’s self-efficacy sources, say Shipherd and Leppma. Here are tips for boosting self-efficacy in yourself and others.

• Make bite-sized goals. Past experience is one of the most potent sources of self-efficacy and that’s why it’s crucial to set achievable goals that build on prior success, says Leppma. Goals that are too far out of reach can lead to discouragement and diminish self-efficacy.

• Find role models. Studies suggest other people are powerful sources of self-efficacy. One way models can inspire others is by sharing how they overcame setbacks rather than giving up, says Leppma.

• Get training. Explicit instruction can help boost self-efficacy, per research.

• Try healthy self-talk. Remind yourself that you’ve done this before or that you’ve been practicing and are ready to level up, says Shipherd.

• Be a cheerleader. Encourage yourself (and others) that you’ll be capable of performing the task. A parent could tell their child, “Wow, you worked really hard on that,” or “Look at the way you figured that out,” says Leppma.

• Use imagery. Picture yourself successfully completing the task to help it feel more possible, says Shipherd.

• Manage your feelings. Anxiety, stress, and worry make it difficult to believe you can do what you set out to do. Compassion, mindfulness, and reframing negative thoughts can help switch your thinking so you feel more capable, says Leppma.

• Reframe discomfort. If you’re frustrated, tell yourself it’s a normal part of the process, says Shipherd. A distance runner might remind themselves that there’s always a point where your legs hurt a bit, but that sensation is a sign you’re working hard and can keep pushing, not a cue to stop, she says.

• Take care of your body. When you’re tired, in pain, or nervous, it’s hard to feel like you can do what you need to do, notes Shipherd. She points out that athletes can improve self-efficacy by taking time for appropriate recovery so they aren’t feeling any pain or fatigue before their workout even starts.

Can you have too much self-efficacy? Like any belief, it’s possible that someone could have self-efficacy that’s so excessive that it’s out of touch with reality, says Maddux. Someone with narcissistic or grandiose traits, for instance, might have unrealistically high expectations about what they can do.

Overly elevated self-efficacy could make forming a solid plan for achieving your objectives more difficult. Then, when things don't work out as fast as you would like them to, you could become discouraged and give up, says Maddux. Research supports the idea that overconfidence can sever the generally solid connection between self-efficacy and performance.

Still, on balance, self-efficacy is generally considered to be a good thing. “I wouldn't worry too much about people who are highly confident in their ability to accomplish things,” says Maddux. “They probably would be more likely than the rest of us to achieve those things.”

Favorite Orgs for Essential Self-Efficacy Info

American Psychological Association (APA)

The APA is considered the leading organization for professional psychology, so you know you can trust their teaching tip sheet on self-efficacy. This one recaps the research on self-efficacy and goes into detail about how self-efficacy theory has been explored as a tool for preventing HIV.

Transforming Education

Aimed toward teachers, this toolkit has something for everyone, regardless of whether you’re in education. If you love a slide deck, you’ll want to scroll through the PowerPoint on self-efficacy, which hits all the high points (including why self-efficacy matters and how to boost it). If you’re all about animation, you can press play on the 4-minute video for their summary of self-efficacy.

Favorite Self-Efficacy Podcast

Strength Running Podcast

Episode 166 ("Dr. Amber Shipherd On Building Confidence, Self-Efficacy, And Positive Self-Talk") digs into practical ways that runners can boost self-efficacy to improve performance. But honestly, the advice is so spot-on for so many situations that even nonrunners will be nodding along and taking notes.

Favorite Self-Efficacy Video

TEDx: ‘Why Self-Efficacy Matters’ by Mamie Morrow

Like all the best TEDx Talks, by the end of this one (which has 92k views), you’ll want to stand up and cheer. Educator Mamie Morrow, master of education, makes the case for the importance of self-efficacy, which she calls “the fuel that drives change.” Warning: It may leave you feeling inspired.

Favorite Book on Self-Efficacy

‘Self-Efficacy: The Exercise of Control’ by Albert Bandura

Written by the man himself, Albert Bandura (aka the psychologist who developed the theory of self-efficacy), this book is the best you can get on the subject. It’s no easy, breezy beach read, but for a deep dive into self-efficacy, it can’t be beat.

Favorite Self-Efficacy Planner

Ink+Volt Goal Planning Pad

Setting just-right goals is a terrific way to build self-efficacy, and we love how easy (and pretty) this planning pad makes what can be a frankly intimidating process. On a single sheet, you can nail down the goal you’re after, list specific steps to get there, brainstorm how you’ll deal with inevitable obstacles, and document encouraging messages for the inevitable challenges you’ll face. It’s an excellent resource for DIY self-efficacy support.

Favorite Resources for Finding Individual Self-Efficacy Support

Association for Applied Sport Psychology (AASP)

Certified Mental Performance Consultant (CMPC for short) is a credential from AASP for master’s or doctoral-level experts who can help you build self-efficacy, says Shipherd. This database lets you search for CMPCs who can help you in sports, exercise, business, art, and other domains. You can also filter by location and specialization, which covers goals like managing burnout, stress management, and disability. We love that you can opt for in-person or online sessions and know that either way, you’re connecting with a trained professional committed to the science.

FindTreatment.gov

Traditional mental health therapy can go a long way toward building self-efficacy. With this free resource, you can plug in your location and select your preferred treatment approach to find a licensed therapist near you. Cognitive behavioral therapy (CBT), in particular, shines a light on how your thoughts, feelings, and behaviors are linked and can give you concrete strategies for shifting to a can-do attitude.