Researchers from the University of Bath in the U.K. say that while positive thinking and optimism are often associated with success in life, their new study suggests these traits may signify low cognition and often lead to poor decision making in finances, according to Medical News Today,

The study found that intelligent people perform better in money matters because they are realistic about making plans and setting goals.

Their study found that people with the highest cognitive ability are 22% more likely to be realistic or even pessimistic in financial planning, with a 34.8% reduction in optimism compared to people of low cognitive ability. Low cognitive skills were measured by verbal fluency, fluid reasoning, and memory says Neuroscience News.

Overly optimistic people tend to anticipate unrealistically positive outcomes when making business moves, investing and other fiscal activities. This may result in loss of funds, debt, and business failures.

“My results indicate that low cognitive ability leads to an increased probability of just self-flattering biases. Humans are primed to be optimistic,” said lead author Chris Dawson, associate professor of Management, Marketing, Business & Society at the University of Bath. “Intelligence governs the ease to which the primed response can be overridden when important financial decisions have to be made.”

Dawson told Medical News Today that “realists make accurate judgments of the future, and pessimists are those that overestimate the likelihood of bad things happening.” He added that both pessimism and optimism may taint one’s view of future financial outcomes with the former being overly negative and the latter being overly positive.

But experts say that optimism and positive thinking has some benefits in the real world. They can provide motivation, have social benefits, and can make people feel good about themselves. However, Dawson cautions that when it comes to decision-making, especially big decisions regarding investments and careers, having realistic expectations will always deliver better decision-making and better outcomes for individuals. Dawson says his research has found that realistic people are the happiest.

“Unrealistic optimism is one of the most pervasive human traits and research has shown people consistently underestimate the negative and accentuate the positive,” says Dawson. “The concept of ‘positive thinking’ is almost unquestioningly embedded in our culture — and it would be healthy to revisit that belief.”