Each year, new MIT graduate students are tasked with the momentous decision of choosing a research group that will serve as their home for the next several years. Among many questions they face: join an established research effort, or work with a new faculty member in a growing group?Professors Cynthia Breazeal, leading a group of over 30 students, and Ming Guo, with a lab of fewer than 10, demonstrate that excellent mentorship can thrive in a research group of any size.Cynthia Breazeal: Flexible leadershipCynthia Breazeal is a professor of media…