Overcoming a basic psychological barrier could be the difference between earning just enough and getting rich

The critical difference between wealthy and average people is not found in their education, luck, skills, or choice of investments - it's found in their mindset.

"The biggest thing holding back most people from striking it big are their thoughts, beliefs and philosophies about money," writes self-made millionaire and author of "How Rich People Think," Steve Siebold.

Certified financial planner Douglas Obey echoes this belief in his book, "Money & The Human Condition." Average people sabotage themselves psychologically from accumulating wealth, he writes.

Specifically, one severe roadblock holds many of us back from getting rich: fear.

"The fear of rejection holds us back from asking for opportunities. The fear of failure prevents us from working on goals to reach our dreams," he writes.

"The fear of success prevents us from reaching our full potential because if we succeed, a precedent has been set, one that we will be expected to continue in the future, creating more pressure than many of us feel capable of handling."

We don't reach beyond who we believe we are, and so we never achieve beyond who we believe we are. "In our own minds, we cling to a certain level of success that ends up defining us," Obey says.

Oftentimes, we can attain more than what we settle for, but we convince ourselves that we don't need or deserve a certain amount of money. "The process of building and acquiring wealth feels out of reach, impossible to most," he writes. "So why bother even trying?"

Obey uses his personal story as an example. In the 1980s he worked in financial services making $30,000 a year - his "magic number" that he had dreamt of earning since high school. He worked hard - really hard - and often logged more hours than his peers, but he continued to under-perform.

It was inexplicable, until his firm brought in a psychologist who explained the "fear of success" barrier.

"It was identified that, once I hit my self-proclaimed, subconscious 'limit' of $30,000 per year, I would begin the process of sabotaging myself, preventing myself from making any more," he explains. "Anything beyond this self-proclaimed ceiling I dismissed as being well-off (if not wealthy) - an amount which someone of my stature in life neither deserved nor could attain."

The realization prompted him to stop the self-defeating cycle. By the next year, he had doubled his income.

This psychological fear is difficult to identify and comprehend, he emphasizes, but becoming aware of it - and learning to overcome it - can be the difference between being average and getting rich.