Blogger DrugMonkey is polling his readers to see whether they've ever been told that changing locations between PhD-, postdoc-, and junior faculty-work bolsters their image as more "committed to science" in any way. Out of 466 votes so far, 51 respondents indicate that they've been told "If you do not change locations between grad, post-doc and/or faculty positions you are not committed to science," at some point during their careers. The largest group — 139 voters — indicated that they'd been advised that while switching institutions isn't necessary, "you will definitely be a better scientist if you do."
Janet Stemwedel at Adventures in Ethics and Science expands on the topic, and suggests that for researchers who intend to attain lifelong careers in academia, "there is certainly something that could be useful about gaining firsthand experience of a number of different academic institutions — if for no other reason that the cultures of various colleges and universities can vary quite widely (as can how secure or precarious their funding situations are, what this does to the state of facilities and administrative support, not to mention teaching loads, etc.)." Additionally, she says, a potential applicant's propensity to change geographical regions and institutions may be appealing to search committees. But, she continues, "it's not clear to me that preferring the rootless candidate who is married first and foremost to science is always the best hiring move," adding, "Why, for example, would you not view such a scientist as a flight risk — the kind of person who might, at the drop of a hat, run off and do more exciting science with some other institution far away?"