Another nugget of evidence comes from the phrase “fifty-fifty.” To careful probabilistic thinkers, 50% is just one in a huge range of settings, so they are no likelier to use it than 49% or 51%. Forecasters who use a three-setting mental dial are much likelier to use 50% when they are asked to make probabilistic judgments because they use it as a stand-in for maybe. Hence, we should expect frequent users of 50% to be less accurate. And that’s exactly what the tournament data show.
