Danila Serra, a professor and economist at Southern Methodist University, wasn’t sure she wanted to pursue a Ph.D in economics. Then she spent half an hour with then-University of Oxford professor Abigail Barr, the woman who would become her advisor.

“It took 30 minutes, just one conversation, for me to decide about the Ph.D even though until that point I wasn’t sure and I had lots of doubts,” Serra told Moneyish. “After talking with her, I was totally sold on it.” Barr’s energy, charisma and positivity — coupled with a discussion of her research — made up Serra’s mind, she said.

Years later, armed with grant money from the Undergraduate Women in Economics Challenge, Serra set out to simulate her own experience at SMU — and found a mere 15-minute exposure to inspiring female role models spurred top-performing college women to pursue econ majors. The experiment was especially crucial in such a male-dominated field, she added: “It’s very difficult for a young woman to come into contact with an interesting woman, a career woman who is doing a job interesting in the eye of the student,” she said. “There are so few women in the field that basically it’s not easy to meet someone … that can inspire you to do the same.”

Serra enlisted two female former students, Emily Towler and Tracy Nelson, to help select classroom speakers who would be “inspiring to young female students,” she said. The two pored over decades of SMU economics alumni to compile an 18-name shortlist, then conducted Skype interviews with candidates.

They landed on 2008 alum Julie Lutz, who left management consulting to work at an NGO in Nicaragua and later a Honduras-based toy company, and 1991 alum Courtney Thompson, who harnessed her economics degree into a successful marketing career. “We wanted someone who would capture and retain attention, but also someone who we thought people would find aspirational,” Nelson, now a second-year Yale Law student, told Moneyish.

Lutz and Thompson, instructed to discuss their career paths in an engaging way, gave 15-minute talks to four randomly selected Principles of Economics classes at SMU. Exposure to the role models made it 12% more likely that a female student would pursue an intermediate economics class the next year, and 7.8% more likely she would “express the intention to major in economics.” The effect was even more dramatic among women with a 3.7 GPA or higher, with a 26% greater likelihood of entering intermediate econ and a 12% greater likelihood of majoring in econ. Male students, Serra added, were “totally unaffected.”

The impact of these brief visits indicates “role models are more important than we think,” Serra said. “I thought that there might be an impact; I thought this could work, but definitely I did not expect such a large impact coming from such short visits.”

Towler, now a ninth-grade Spanish teacher in Dallas, Texas, remained unsurprised by the study results. “I think it kind of falls into place with the adage … ‘You can’t be what you can’t see,’” she told Moneyish. “When you see a woman who studies economics, then it definitely seems to open up some doors.”

The field experiment could certainly be applied to other male-dominated fields and different student populations, Serra said. But “the role model needs to be somebody that students can identify with,” she said. “I don’t think that somebody that gives a TED Talk, for example, or a famous professor or famous businessman or famous personality might necessarily have an impact on young female students.” To that end, she said, it was important that the role models in the study had pursued interesting careers after majoring in econ at SMU.

It’s vital to attract women to fields that are not only male-dominated, but have high earning potential, Serra added. “One way to getting closer to close the gender pay gap, or (the) gender gap in leadership positions,” she said, “is to actually induce more women to choose that field of study that lead to these high-paying careers.”