One of the things that Haidt leaves out of his article is that the % of difference between liberals and conservatives was within the margin of error.

His findings have also never been validated, even by other conservative scholars, and he refuses to provide the data from this study. (Also, the study was a survey given to people attending the Reagan Library during the work week, so a highly self-selective bunch...)

(Jonathan Haidt was a hero of one of my professors...until the scholarly issues with Haidt's research came to light.)