Centrists aren’t typically well-informed people who understand fully the strengths and weaknesses of the arguments of the left and the right. Centrists aren’t normally Mickey Kaus writing a ten-part debate with himself over whether to vote for Gore or Bush in 2000 (he eventually decided upon Gore).
Instead, centrists are more often people who find politics boring and annoying and wish it would just go away.
The GSS permits a testing of that assertion. The following graph shows a political interest by self-described ideology. The survey asked respondents about their personal level of interest in politics with five potential responses ranging from "not at all interested" on the low end to "very interested" on the high end. Inverted from the survey for ease of comprehension, the higher the score, the greater the interest (N = 5,091):
Steve's assessment is spot on.
Relatedly, moderates tend to be less intelligent than liberals or conservatives. Dumbest of all are self-described conservative Democrats and liberal Republicans, probably because many of them are just randomly selecting designations due to ignorance and a fear of being recognized for that ignorance.
GSS variables used: POLVIEWS, POLINT