Important phenomena in the area of judgment and decision making may be profitably studied with behavior-analytical techniques. We discuss three examples of such research: base-rate neglect, in which people ignore critical background information in favor of less reliable case-specific information; the conjunction fallacy, in which people report that the conjunction of two events is more likely to have occurred than one of the events alone; and the sunk-cost effect, in which people are unwilling to abandon a course of action which has already incurred substantial cost. **********
