Effects of Mutilation Images on Self-Control Behavior and Delay Discounting

Abstract

Flora et al. (1992; 2003) found that intense noise and cold water decreased self-control responses during a task in which college students chose between smaller-sooner (SS) and larger-later (LL) options to earn points exchangeable for money (SS – impulsive option; LL – self-control option). Flora et al. also observed that the removal of the aversive stimulus did not result in increments in LL responses, and vice versa (i.e., self-control preference continued when the noise was later introduced). Considering human physiological responses to pictures of human mutilation resemble those produced by aversive stimuli (e.g., heart rate changes), we explored if the disruptive effects of aversive stimuli on self-control behavior could be reproduced with images of mutilation. Flora et al.’s (1992) and Hurtado-Parrado et al.’s (2023) tasks were replicated. Matching-to-sample trials depicting the images of mutilation were interspersed between the choice trials with different probabilities (Random-Time 0, 20, and 30). A delay-discounting task was introduced before and after the choice task to obtain k and Area Under the Curve (AUC) values, which were used to explore a relationship with performance during the choice task. A single-case experimental design was implemented with 24 participants. Each probability of mutilation images was an experimental condition. Initial exposure to high probability of mutilation images overall produced indifference (approximately 50% LL responses). LL responses increased when the probability of the images was reduced. Participants not initially exposed to the images mostly maintained self-control preference when images increased in probability. Delay-discounting measures were not related to performance during the choice task, possibly because of a magnitude effect (smaller reinforcers are discounted more steeply than larger reinforcers). Future studies must address the divergent results in this line of research, including that noise and visual stimulation produced mostly indifference, whereas cold water is the only stimulus that has increased impulsive choice beyond indifference