I went to a New England liberal arts college, like Colgate, and the most popular major at my school was Economics, which is categorized as Social Science. Most of the Econ graduates went for jobs in management consulting or investment banking, as those companies would come to recruit on campus, and tend to already have a solid number of alums working there to begin with. In fact, Dick Fuld, the ex-CEO of the infamous Lehman Brothers investment bank, was a trustee on the board of my school, and hired many alums, as did Goldman, Morgan Stanley, Credit Suisse, etc.
For banking jobs straight out of undergrad, you don't have to have a deep understanding of quantitative finance. It's more about having a soiid GPA, a demonstrated interest in the topic and interest in learning, and the capacity to work very, very long hours.