We investigate with a cross-sectional study, looking at proto-rationalists versus experienced rationalists. Define proto-rationalists as those respondents to the Less Wrong survey who indicate they have been in the community for less than six months and have zero karma (usually indicative of never having posted a comment). And define experienced rationalists as those respondents to the Less Wrong survey who indicate they have been in the community for over two years and have >1000 karma (usually indicative of having written many well-received posts).

This is an incredibly bad definition of a rationalist. What you actually research here are people who fit into the mainstream of LW.