If you believe you’ll never make CEO, start a company, lose weight, or any other goal, no matter how much you change your behavior to achieve it, your belief will undermine that behavior. If you’re lucky, you may stumble into an experience that changes your beliefs, which may sustain your behavior, but I wouldn’t count on it.

In general, if you change behavior but not the belief that motivated the old behavior, the old behavior will likely return. That old behavior is consistent with that view of the world.

Remember, you don’t choose or act based on reality. You choose and act based on your beliefs about the world. Your brain only acts based on what’s in your head, which your senses and beliefs filter from the outside world.

If you change your beliefs but not your behavior, you have a chance that your behavior will change to match your new perspective. If you believe you’ll become rich, when life gives you choices leading to making money or not, like what friends you spend time with or what you major in, you’ll tend to move in directions toward money. Nothing special about money. The same happens in all parts of your life.

If I had to choose only one of behavior or belief to change to try to create a sustainable change, I’d pick belief. It may take longer to stick and propagate to your behavior, but I find it more likely.

I recommend changing both belief and behavior, of course, along with your environment. Then the change is most likely to stick.

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