It's the mantra of creative icon Steve Jobs, serial entrepreneur Russell Simmons, and other accomplished executives: In order to succeed at your job, you have to do what you love. 

But one study, published recently in the Personality and Social Psychology Bulletin, indicates that passion for your job isn't something you have to have on day one for a fulfilling career. 

Researchers from the University of Michigan and the University of Southern California asked almost 900 total participants in four different studies questions about their line of work, including how they selected their current jobs, and how passionate they were about their jobs now compared to where they started. What they found was that both people who began with enthusiasm, as well as those who didn't but believed their passion would grow, could wind up equally satisfied later in their careers.

Patricia Chen, the study's lead author and a doctoral psychology student at the Univeristy of Michigan, says that she was inspired to research job passion after many of her friends, students, and family members were experiencing quarter-life crises. The oft-repeated advice, "follow your passion," wasn't doing them any good, especially for those who didn't have any definitive answers for what they were passionate about. 

When it comes to job passion, Chen says, people typically fall into one of two categories: fit theorists and develop theorisists. Fit theorists believe that in order to be happy at a job, they must be passionate about it from day one. They tend to prioritize job enjoyment at the expense of other vocational characteristics such as pay. 

"Because of this mentality, they are motivated to select into vocations they think they will enjoy right from the get go," says Chen. 

Meanwhile, develop theorists don't expect their passion for their job to remain consistent over time. When picking out a job, they prioritize other criteria over whether or not they're in love with what they do. They believe that their enthusiasm for a job will grow as they become better at it, and don't view a lack of passion for the work as a deal-breaker.

One important note is that Chen and her researchers only tested passion against pay when determing how satisfied people were with their jobs--that is, study particpants either prioritized enthusiasm for the job over salary, or vice versa. Future research might indicate whether develop theorists are still as likely to be satisfied in their careers compared to fit theorists if they choose a job because it offers a better work-life balance, for example. 

Regardless, the study offers up an interesting challenge to the notion that, especially as an entrepreneur, you can't succeed without passion. Take Uber cofounders Travis Kalanick and Garrett Camp. As Inc. columnist Jason Fried points out, they "didn't start their ride-sharing service because they loved transportation or logistics. They started it because they were pissed off that they couldn't get a cab in San Francisco."