How do people make decisions? There is a class of models in psychology which seek to answer this question but have received scant attention in economics despite some clear empirical successes. In a previous post I discussed one of these, Decision by Sampling, and this post will look at another: the so-called Fast and Frugal heuristics pioneered by the German psychologist Gerd Gigerenzer. Here the individual seeks out sufficient information to make a reasonable decision. They are ‘fast’ because they do not require massive computational effort to make a decision so can be done in seconds, and they are ‘frugal’ because they use as little information as possible to make the decision effectively.