Here is the abstract from a study by O’keefe, Dweck and Walton:

People are often told to find their passion as though passions and interests are pre-formed and must simply be discovered. This idea, however, has hidden motivational implications. Five studies examined implicit theories of interest—the idea that personal interests are relatively fixed (fixed theory) or developed (growth theory). Whether assessed or experimentally induced, a fixed theory was more likely to dampen interest in areas outside people’s existing interests (Studies 1–3). Those endorsing a fixed theory were also more likely to anticipate boundless motivation when passions were found, not anticipating possible difficulties (Study 4). Moreover, when engaging in a new interest became difficult, interest flagged significantly more for people induced to hold a fixed than a growth theory of interest (Study 5). Urging people to find their passion may lead them to put all their eggs in one basket but then to drop that basket when it becomes difficult to carry.

Here is the story from Quartz:

O’Keefe says that these findings can be applied to our individual lives and society. By encouraging a growth mindset in schools, demonstrating it in our approach to information, and minding our mantras, students and all of the other people we encounter might be more inclined to adopting a growth mindset, too. “There’s no problem with encouraging students to pursue that one ‘thing,’” he says, “But why can’t that ‘thing’ be informed and complemented by the world of knowledge that exists?”

Adopting a growth mindset won’t turn you into a superficial generalist. But it could help you better understand the topics you’ve chosen to master. “Our work shows that a growth mindset increases interest in areas outside of students’ pre-existing interests. Furthermore, this newly developed interest does not appear to detract from their pre-existing interests. In other words, by encouraging a growth mindset, we don’t see evidence that students become dilettantes. Instead, they might be seeing connections among new areas and the interests they already have. That’s a powerful learning tool,” says O’Keefe.