Thanks for writing this!This is very reasonable; 'no predictive power' is a simplification.
Purely academically, I am sure a well-reasoned Bayesian approach would get us closer to the truth. But I think the conclusions drawn still make sense for three reasons.
Thanks for the comment! I think it's completely plausible that these two measures were systematically measuring something other than what we took them to be measuring. The confusing thing is what it indeed was measuring and why these traits had negative effects.(The way we judged open-mindedness, for example, was by asking applicants to write down an instance where they changed their minds in response to evidence.)But I do think the most likely case is the small sample.