Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Karen G. Anderson.


The sunk-cost effect is a decision-making fallacy that has its origins in the discipline in economics. In general, sunk-cost situations are typified by the presence of an initial investment that is followed by behavioral persistence, especially in the face of progressively worsening outcomes. This fallacy occurs when individuals use past expenditures (i.e., sunk costs) rather than future costs to guide decisions. Although there is a growing body of literature involving human participants, relatively little work has been done examining the variables that govern the sunk-cost effect in nonhuman subjects. The present experiments examined effects of response effort, delay, and stimulus changes on the sunk-cost effect in an animal model. In this procedure, pigeons responded on increasing ratio schedules of food reinforcement. In some conditions, the center keylight changed as the ratio increased (i.e., the increase was signaled). Responses on another alternative reset the ratio requirement to the lowest value, serving as an escape from the increasing ratios. In general, persistence was more likely to occur in the absence of the signals and when the delay to the onset of the next trial was relatively long or when the response requirement to escape was relatively high.