Interview participants reported that TD research introduced unique conceptual and scientific challenges compared to approaches closer to the unidisciplinary end of the research continuum. They described how the work of TD integration “stretched” their intellectual capacity more than typical scientific endeavors, and also stated that the challenges increased with the number of disciplines represented in a TD research team. If someone is coming in with a research question that might be valid in a different field, but looks really strange to you, I think it's quite difficult to change the way you think, to integrate research questions that you're not familiar with.