Dunno... If you treat it as a zero-sum game (i.e. you don't only want your answer to be close to 80% of the average answer, but you also want other people's answers to be far from it) it's not obvious to me that you should vote 0.

I was granting for the purpose of responding that loup-vailant's clear assumption that normal game theory principles apply---each agent is interested only in the payoffs to itself to the exclusion of all else and the payoffs are such that it gets 0 for being wrong and >0 for being right.

It so happens that my own actual response (100%) doesn't conform to those assumptions. In fact my original reply to:

Minimize the expected square of the distance between your answer and 80% of the mean of the answers chosen:

... was "No", and my original reply to loup-vaillant pontificated about the complete lack of payoff to any of the radio buttons. However I abandoned that point because the point about it not mattering whether the other guy is using CDT or TDT actually matters (somewhat).

In this game (ie. with an actual assumed payoff for correct and no negative payoff for other's success) the Nash equilibrium (and the outcome that a group of all CDT agents would pick) also happens to be pareto optimal. In fact, it outright gives the maximum possible payoff to every individual. Even inferior decision theories can pull that off.