In this talk I will start with a brief review of recent discourse about interdisciplinarity, especially focusing on a popular distinction between inter- and multidisciplinarity and the related notion of ‘integration’. Next, I will present an analytical approach that can be used for examining research activities that cross boundaries between disciplines, subdisciplines or research fields. I shall argue that compared to the standard taxonomy of inter-, multi- and transdisciplinarity, this analytical approach provides a more nuanced understanding of the crossing of intellectual boundaries, and of how balances between benefits and drawbacks may vary depending on both cognitive and social factors.