Effects of depression on reward-based decision making and variability of action in probabilistic learning

• Published in: Journal of behavior therapy and experimental psychiatry Vol. 43; no. 4; pp. 1088 - 1094
• Main Authors: Kunisato, Yoshihiko, Okamoto, Yasumasa, Ueda, Kazutaka, Onoda, Keiichi, Okada, Go, Yoshimura, Shinpei, Suzuki, Shin-ichi, Samejima, Kazuyuki, Yamawaki, Shigeto
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2012; Elsevier
• Subjects: Adult and adolescent clinical studies; Biological and medical sciences; Decision Making; Depression; Depression - psychology; Depressive Disorder - psychology; Female; Humans; Learning; Male; Medical sciences; Mood disorders; Parameters; Probabilistic learning; Probability Learning; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Reinforcement; Reinforcement (Psychology); Reinforcement learning; Reward; Reward sensitivity; Variability; Variability of action selection; Young Adult; Variability of action selection; Depression; Probabilistic learning; Reward sensitivity; Decision making; Reinforcement learning; Mood disorder; Human; Acquisition process; Response selection; Probability learning; Reward
• ISSN: 0005-7916; 1873-7943; 1873-7943
• DOI: 10.1016/j.jbtep.2012.05.007

Depression is characterized by low reward sensitivity in behavioral studies applying signal detection theory. We examined deficits in reward-based decision making in depressed participants during a probabilistic learning task, and used a reinforcement learning model to examine learning parameters during the task. Thirty-six nonclinical undergraduates completed a probabilistic selection task. Participants were divided into depressed and non-depressed groups based on Center for Epidemiologic Studies–Depression (CES-D) cut scores. We then applied a reinforcement learning model to every participant's behavioral data. Depressed participants showed a reward-based decision making deficit and higher levels of the learning parameter τ, which modulates variability of action selection, as compared to non-depressed participants. Highly variable action selection is more random and characterized by difficulties with selecting a specific course of action. These results suggest that depression is characterized by deficits in reward-based decision making as well as high variability in terms of action selection. ► Depressed subjects showed lower reward-based decision making than non-depressed subjects. ► Depression did not affect on the punishment based decision making. ► Depressed subjects showed higher learning parameter τ than non-depressed subjects.