What does Caroline Kennedy know that we don't?

Recently the New York Times posted audio clips of an interview with Caroline Kennedy discussing her potential selection to the U.S. Senate. Sheila McClear noted on Gawker that Kennedy says "you know" 12 times in the first 49 seconds. "We can't listen to two years of this!," McClear wrote. "Caroline: every pause need not be filled with wordage, you know?" The Times soon changed the headline from "As a Candidate, Kennedy Is Eloquent but Elusive" to "...Forceful but Elusive." But what does saying "you know" actually say, you know, about your personality?

Using the phrase is a pet peeve of my mom's. She'll interrupt my dad and say, "No, I don't know--you haven't told me yet." I suppose the peeve has latched onto me, as I'm more aware than most people are of its use.

In 2007 I asked the U Penn linguist Mark Liberman if there might be differences between people who say "I mean" a lot and those who say "you know" a lot. He did some analysis and found that the "you know"/"I mean" ratio is greater in women and those who are older and those who are less well educated. Later he found that the uses of "you know" per conversational turn is highest in people 40-59, and is greater in men. But these data don't say much about personality.

About a year ago I asked UC Riverside psychologist Lisa Fast about you-know-ers and I-mean-ers. She'd published a paper in the Journal of Personality and Social Psychology titled "Personality as Manifest in Word Use: Correlations With Self-Report, Acquaintance Report, and Behavior," and she performed some additional analysis of the data for me.

Fast used a program called Linguistic Inquiry and Word Count and found that women use more nonfluencies (phrases such as "you know" and "I mean") and fillers (words including "um" and "uh") than men do. Both men and women who use more nonfluencies and fillers are considered by their peers to be more extroverted and more agreeable. Academic achievement is not correlated. She wrote me, with the caveat that no one has a real theory about the matter:

It seems possible that use of nonfluencies mark uncertainty in one's ability to effectively communicate and that use of filler words mark hesitation in speech. Perhaps those who use more of these words are generally less sure of themselves, and are therefore perceived by those who know them well as less sociable, yet perceived as better able to get along with others because they are linguistically humble.

So it seems the second Times headline isn't perfect either. According to the nonfluency factor, Kennedy is neither forceful nor elusive. Most woman who talk like that would be perceived as, you know, accommodating and outgoing. And certainly more equivocal than elusive.

Or something.

UPDATE: In this week's New Yorker, Ben McGrath refers to a 2001 essay by Berkeley linguist Robin Lakoff entitled "Now You Know About Hillary Rodham Clinton" in which Lakoff speculates that Clinton's liberal use of "you know" might signal vulnerability. (Clinton had used the phrase 19 times during a press conference regarding Bill's presidential pardons.) Lakoff wrote: "Senator Clinton keeps using you know, whether hopefully or desperately, as a plea: 'Please see it my way—because we share the same world-view.'"