On each trial, participants choose between a risky and safe option. Each trial involves either gains or losses. The options are presented as a choice of cups. The risky option involves two to five cups, one containing a gain (loss) of $2, $3 or $5, and the others containing $0. If the latter option is selected, the payoff from one cup is selected at random. The safe cup offers a sure gain (loss) $1.
Definition contributed by RPoldrack about six months ago.