Not guppies, nor goldfish, but tumble dryers, Noriega, Jesse Jackson, panties, car crashes, bird books, and Stevie Wonder.

This paper focuses on the guppy effect (Osherson & Smith, 1981), that is, on the existence of examples of conjunctive concepts that are more typical of the conjunction than of both constituents. The most frequently given examples of this effect, guppy and goldfish, are shown not to be more typical of the conjunction pet fish than of fish in two between-subjects and one within-subjects experiment. The frequency of the effect in a large empirical study is investigated, and better examples of the effect are suggested.