Appetitive Motivation in Depressive Anhedonia: Effects of Piece-Rate Cash Rewards on Cardiac and Behavioral Outcomes.

Abstract

Deficits in self-regulation and motivation are central to depression. Using motivational intensity theory (Brehm & Self, 1989), the present research examined how depressive anhedonia influences effort during a piece-rate appetitive task. In piece-rate tasks, people can work at their own pace and are rewarded for each correct response, so they can gain rewards more quickly by expending more effort. A sample of community adults (n = 78) was evaluated for depressive anhedonia using a structured clinical interview, yielding depressive anhedonia and control groups. Participants completed a self-paced cognitive task, and each correct response yielded a cash reward (3 cents or 15 cents, manipulated within-person). Using impedance cardiography, effort-related physiological activity was assessed via the cardiac pre-ejection period (PEP). The results indicated lower reward responsiveness in the anhedonia group. Compared to the control group, the depressive anhedonia group showed significantly less baseline-to-task change in PEP, and they performed marginally worse on the task. The experiment supports the predictions made by applying motivational intensity theory to depression and offers a useful paradigm for evaluating anhedonic effects on effort while people are striving for appealing rewards.