From William Pannapacker, aka Thomas H. Benton, here and here. From the second essay:

Essentially I see students having difficulty following or making extended analytical arguments. In particular, they tend to use easily obtained, superficial, and unreliable online sources as a way of satisfying minimal requirements for citations rather than seeking more authoritative sources in the library and online. Without much evidence at their disposal, they tend to fall back on their feelings, which are personal and, they think, beyond questioning.

This is exactly what I found with students at George Mason. In my instructions for a particular assignment, I had to write,

the paper is not about you and why you chose a particular highlight. Instead, your focus should be on an objective explanation of the issue that you chose to highlight from the unit.

Where I differ with Pannapacker is that I am not sure that the issue is entirely generational. It could be that the current generation of high school graduates includes plenty of students who can make analytical arguments. But we are attempting to shove more high school students into college, and so many college professors are seeing more students who cannot make analytical arguments.

Speaking of which, Charles Murray will be talking this evening. Might be worth stopping by.