I'd upvote this twice if I could.

The weighted probability curve reminded me of some other research I first heard of a couple of years ago, to do with human choices being made by comparing them to their neighbouring choices, rather than on an absolute scale of utility. The result of this being that people find it hard to appraise things on more than five levels of gradation ("worse", "this", "better", and intervals between them). This provides a plausible explanation for why we rank so many things out of five.

I looked for the research in question, and found Decision by Sampling. Having now had a look at the actual paper, it actually references prospect theory twice. I really should follow these things up more.