One of the prompts for the Brown supplement is:
Why are you drawn to the area(s) of study you indicated earlier in this application? If you are “undecided” or not sure which Brown concentrations match your interests, consider describing more generally the academic topics or modes of thought that engage you currently. (150 word limit)
I wrote my answer about the major itself, but should I add something about how an education in this major will help me in the future or just leave it as is (just about why I want to major in __).