When I joined the PhD program, I was unsure what kind of other people would also be getting their PhD. I decided that I wanted a PhD before I left undergrad so I entered the program the Fall after I graduated. When I visited the PhD program at the university I am now attending, I knew there was some variety in the other candidates as well as in the students currently in the program I met. In the program I joined, maybe a third of the students in OB came directly out of an undergrad program. I have been told that there are some programs in management that typically require you to have a masters degree (in business, statistics, mathematics, etc.) to get real consideration.
When I entered the program, the student that began with me had been a consultant for a number of years after getting an MBA and was also married with a child. Though I think a lot of the other students that started the year I did were unmarried, many had had some background in a job or had done some higher education already. Also, I was a bit surprised by the number of students from South America. As an undergraduate, most foreign students I knew were from Asia or Africa, so I was a little surprised.
More generally, I'd like to give an idea of the kinds of social types of people that are in the PhD program I am in. Though all of them are loosely doing some kind of social science, some groups are much more analytical than others.
Because of the wide range of backgrounds of the students I encounter, there are some rough categories that my social experience kind of classifies them into. Those that have families I see around less in the building itself (for the first 3 years I spent at least some time in the office nearly every day). They often come to social functions that this is where I see them the most often. On the opposite side are those that I always see in the office that also typically don't go to social functions like BBQs (except for the free food). Though I think this is partially because many are working very hard, I think that some like being i the office more than being at home. I have seen students spend time in their office playing games, or surfing the web but also staying until very late hours. I had an office mate at one point that was much like this. I had a running joke that one of us was in the office 24/7 for a while. When I would leave at 10 or 11pm some nights, he'd still be there and he'd still be there when I returned at 8am but would soon leave for a large part of the rest of the morning.
Students that are in joint programs are typically pulled between multiple departments and sometimes multiple buildings, spending half of their time in each place.
There are a lot of experiences in a PhD program - based on my anecdotal experience - and you'll likely encounter a bunch of people with a variety of backgrounds and experiences if you ever join one.
