"Brief statement of research interests" for a social sciences postdoc?

All the other postdoc positions I've applied to just ask for a CV, cover letter, and references. This one also asks for a "brief statement of research interests". I drafted a few short paragraphs, just under 200 words, but I honestly have no idea what is expected here. I talked about my interest in the particular methods and tools their lab has to offer, showing how I envision my interests (which are demonstrated in my prior research) connecting to these things. How long do you think a "brief" research interest statement be?