Here's something that you don't see mentioned very often in science, but it's most certainly real: snobbery:
We all do it. Pressed for time at a meeting, you can only scan the presented abstracts and make snap judgements about what you are going to see. Ideally, these judgements would be based purely on what material is of most scientific interest to you. Instead, we often use other criteria, such as the name of the researchers presenting or their institution. I do it too, passing over abstracts that are more relevant to my work in favour of studies from star universities such as Stanford in California or Harvard in Massachusetts because I assume that these places produce the 'best' science.
As someone who is based at a less well-known institution, the University of South Dakota in Vermillion, I see other scientists doing the same to me and my students. In many cases, this is a loss: to my students and their projects, which could have benefited from the input, and to the investigators who might have missed information that could have been useful in their own work.
It's true. This carries over to industry, too, both in the ways that people look at other's academic backgrounds, and even in terms of industrial pedigrees. Working for a biopharma that's been successful, that everyone's heard of, does a lot more for your reputation than working for one that no one knows anything about. The unspoken supposition is that a really small obscure company must have had to reach lower down the ladder to hire people, even though this might not be the case at all.
I have no idea of what could be done about this, because I think it's sheer human nature. The best we can do, I think, is to realize that it happens and to try to consciously correct for it when we can. It's realistic to assume that some small school doesn't have the resources that a larger one has, or that a professor at one has more trouble attracting students. But beyond that, you have to be careful. Some very smart people have come out of some very obscure backgrounds, and you can't - and shouldn't - assume anything in that line.