I don't know, you know? Discourse markers and knowledge claims

Anyone doing work on discourse markers in English might want to look at Greta Van Susteren's recent interview with Bristol Palin. I find the use of the discourse markers 'you know', 'I don't know', and 'I guess' interesting, especially compared with the actual knowledge claims in the exchange. Here is a sample; the transcript is from FOXNews.com, emphasis added.

VAN SUSTEREN: You know, it always is sort of a difficult thing, you know, when it's a question of youth, and no one ever really knows what to say to a young person in your situation.

BRISTOL: Yes. I don't know. I just -- I hope that people learn from my story and just, like, I don't know, prevent teen pregnancy, I guess.

VAN SUSTEREN: What happened at school?

BRISTOL: I was -- it was during summer and school had just gotten out, so I just knew that I had to finish up high school and focus on getting an education.

VAN SUSTEREN: You know -- you know, we all learned about it in August or so, after -- and the media, I guess, dogged you a little bit.

BRISTOL: Yes.

VAN SUSTEREN: What was your reaction to that?

BRISTOL: I mostly just didn't pay attention to it because my family's strong and it doesn't matter what the -- like, what tabloids say or anything like that.

VAN SUSTEREN: Did you read any of the tabloids?

BRISTOL: I've seen some of them, and I think people out there are just evil because they don't know what was going on at all.

Even if the intelligence of a single person can be buffeted by framing and other bounds on rationality, this does not mean that we cannot hope for something better from the fruits of many people thinking together--that is, from the collective intelligence in institutions such as history, journalism, and science, which have been explicitly designed to overcome those limitations through open debate and the testing of hypotheses with data.
-Steven Pinker, "Block that Metaphor!" The New Republic, October 2006

A person is smart. People are dumb, panicky dangerous animals and you know it.
-Agent Kay, Men in Black, 1997

Harvard psychologist Steven Pinker believes that people are rational. His review of Whose Freedom? by George Lakoff argues that, contrary to Lakoff's emphasis on the form of political speech, rational human beings pay attention to the logic of ideas rather than mere language. Even when individuals don't, he suggests in the quote above, institutions such as journalism lead us back to this rational course.

Current coverage of "LipstickOnAPig-Gate" (more than 1,500 media mentions since Tuesday, according to Google News) suggests, however, that both individuals and the press as an institution are more excited by form than by rational argument.

Quiz question: Does anyone remember what logical point Obama was trying to make when he deployed this folksy idiom?