Among the comments to my previous post, Heidi and southern prof asked how, if at all, a PI is supposed to address the issue of people dating within his or her research group.
Namely, southern prof asked: I'm a new assistant prof and this happened in my fairly small lab recently whereby two of my students have begun dating. I haven't said anything to them and so far no one's work is suffering but the potential for disruption, drama and loss of productivity is worrying.
Let me say at the outset that I have never supervised two people (students or postdocs) who dated each other. This is probably because I have only supervised a couple of women so far, who both had boyfriends in other research groups at the time, and I think all the men in my group (with one possible exception) have so far been heterosexual.
While I haven't had this exact situation in my research group, southern prof's concern falls under the general and very important issue of how much, if at all, a PI should interfere with the interpersonal relationships among students and postdocs.
I think this question requires one to fall back on one's core principles in running a research group. Sort of a lab constitution, if you will. Mine would be something like this: the purpose of my research program is to (a) advance the state of the art in my specialty, and (b) train new scientists. These two are tightly interwoven and in my mind do not exist without one another, at least in a univeristy setting.
Traning young scientists means that you will equip them with the skills to succeed. Sometimes, that might mean discussing their personal choices, if their choices are interferring with their well-being, their training, or the well-being and traning of others.
Here's an example: one of my students used to keep really erratic hours. He'd be awake at night and asleep during the day, work for long stretches and then crash, take a nap, wake up, recaffeinate, and work until collapsing again. He would also catch any virus around and get sick much more often than my students who kept regular hours, and he often ended up having bad secondary infections. I am no medical expert, but it is common sense that sleep depravation and exhaustion weaken one's immunity. So while I respect that people should have a fair bit of freedom in choosing the hours that they work, he was clearly hurting himself. We have had several long talks on how he needs to sleep at night and work during the day, needs to sleeps enough hours in a stretch, and take the time to eat properly and get some fresh air. Should I not have meddled? The student is an adult, after all. I think not doing anything would have been irresponsible of me, as I would have allowed him to further jeopardize his health.
Another example: presently I have a very good mix of students from all around the world, from several different cultures and religions. They are all getting along very well, and from where I am standing there is no conflict between their personal lifestyles or religious beliefs and working collegially in the group. As long as everyone seems happy and productive, I am happy not to interfere with their interpersonal dynamics. But, this was not always the case. Several years ago I had a couple of mercurial students, one of whom was offensive to my foreign students and was very aggressive about his preferences in terms of politics and religion. Fights were breaking out all the time, and I had to do something as everyone's piece of mind and productivity were suffering. At some point I requested that no discussions of politics and religion happen in the lab. This solved some problems but not all, and the fix was only temporary. Ultimately I had to make one of the problematic persons go; the other one turned out to be fairly easy going once the irritant was removed, and all the other students were relieved.
My point is that sometimes the PI has to meddle. One has to judge according to one's own priorities and ethical standards when to step in.
I think that we as advisors are not just bosses of our students and postdocs, we are also entrusted with their professional development and training, and there cannot be professional development without some personal development and, yes, that sometimes means interactions at a personal level.
Going back to the question of the couple dating in southern prof's lab. I'd say hope for the best, prepare for the worst.
If you are lucky, the students will live happily ever after, become the new Marie and Pierre Curie (sans the radiation poisoning), win Nobel Prize(s) and acknowledge their sage advisor for supporting their relationship.
Worst case scenario, they break up and cannot stand to be in the same room. There is picking sides, plenty of drama, tension in the lab. Productivity and lab morale suffers.
Since you are saying that so far everything looks, you will likely be spared the drama in the near future. Still, my immediate concerns would be:
(a) How is the couple's research progress? I think a small and temporary productivity drop is common whenever students start new relationships, regardless of them being in the same lab. But now that they are dating, it is important for each person in the couple to build (or maintain) their own support group and have somewhat independent graduate school experiences. My husband and I were in grad school together. We didn't work with the same PI, but our PI's were close collaborators and shared student office spaces. Professors would assume that we wanted to sit together, but I was adamant about us NOT sitting in the same office (there is such a thing as too much face time); we wanted our graduate experiences to be our own and I think we succeeded and I think it was important. I recommend it if logistics allows. Talk to them and draw their attention to the fact that now that they are together, it may be a good idea to think about separating their lab work from each other's.
(b) Is anybody else's productivity suffering? Are there people who are embarrased by the new couple (especially if the couple are prone to public displays of affection), for instance people who are modest, perhaps for religious reasons? Is there someone who is jealous? Try to invite all group members to share concerns if they have them, pehaps you can emphasize in a group meeting that harmonious interpersonal relationships in the lab are very important, and that if anyone has concerns that they cannot address themselves they should come see you.
From senior PI's, I hear that they had students or postdocs crying in their office after a break-up or divorce. I don't think any PI seeks this type of involvement in personal affairs, but sometimes may end up facing it. I suppose in this case you simply try your best as a person and an advisor to comfort the trainee, and urge him or her to seek help if they appear seriously distressed.
I think too much personal involvment with one's trainees is bad, but some cannot be avoided. Besides, I am not sure how much exactly is "too much" or "just enough".
I think our duty as PI's is to share our best practices in terms of working as successful scientists in a sustainable fashion. This may involve heart-to-heart talks on a variety of topics. Sometimes being a PI involves cutting a problematic student loose to protect the rest of the group. Often being a PI means being unpopular. But, as is typical when dealing with humans, there is no recipe book enabling one to look up how to deal with a new crisis. The only sure things to fall back on are one's core principles and the strength to adhere to them.