Why do people hurt themselves when they want to feel better? An exploration of the roles of cognitive control and decision making.

Abstract

Nonsuicidal self-injury (NSSI) refers to the intentional damaging of one’s own body tissue without the intent to die as a result. NSSI violates the innate drive for self-preservation, and yet it occurs in over 10% of the general American population. The most common reason reported for engaging in this behavior is for the purpose of reducing or escaping psychological distress. Although NSSI has been a topic of philosophical, clinical, and scientific discourse for centuries, the basic mechanisms that promote this type of behavior are only partially known. Across the three studies that comprise this dissertation, we seek to better understand the psychological processes that might lead someone to hurt themselves in order to find relief from psychological distress. In Study 1, we consider the perspective that NSSI results from a process leading from negative affect to an inability to inhibit behavioral responses to urges for relief. Because we failed to find evidence for an association between cognitive control and NSSI in study 1, we considered an alternative perspective in Studies 2 and 3 – that NSSI may result from a value-based choice, rather than a failure in cognitive control, while experiencing negative affect. In Study 2, we developed and tested two novel behavioral tasks to measure decision-making biases related to relief. Results from Study 2 indicate that people prefer to accept less relief if it requires lower delay time or less cognitive effort than more relief. In Study 3 we tested whether those who have engaged in NSSI experience a greater decision-making sensitivity to the cost of cognitive effort when making choices about relief, and whether this sensitivity is exaggerated while experiencing negative affect. Results from Study 3 suggest that people who engage in NSSI demonstrate a decision-making bias against exerting cognitive effort for relief, but we did not find evidence that negative affect influences this bias for participants with or without a history of NSSI. Together, these studies highlight that decision-making, but perhaps not cognitive control, is a psychological mechanism that may help us understand why people engage in NSSI. Future directions for this line of work include further development of novel approaches to investigate the influence of negative affect on decisions about relief, as well as application of these approaches to better understand and ultimately prevent self-injurious behavior.