Right dorsolateral prefrontal cortex regulates default prosociality preference

Abstract

The dorsolateral prefrontal cortex has been shown to be associated with prosocial behavior. However, the direction of this relationship remains controversial. To resolve inconsistencies in the existing literature, we introduced the concept of default prosociality preference and hypothesized that this preference moderates the relationship between gray matter volume in the dorsolateral prefrontal cortex and prosocial behavior. This study analyzed the data of 168 participants obtained from voxel-based morphometry, 4 types of economic games, and 3 different measures of social value orientation that represent default prosociality preference. Here we show that, in individuals who were consistently classified as proself on the 3 social value orientation measures, gray matter volume in the right dorsolateral prefrontal cortex was positively associated with prosocial behavior. However, in individuals who were consistently classified as prosocial, the direction of this association was vice versa. These results indicate that the right dorsolateral prefrontal cortex regulates default prosociality preference.

Keywords: brain structure; dorsolateral prefrontal cortex; economic game; social value orientation; voxel-based morphometry.

Fig. 1

Schematic representation of the relationship between the default preference for prosociality and prosocial behaviors. In proselfs, the default preference for prosociality is low; therefore, selfish behavior, owing to consistency, can be performed quickly. However, when they engage in prosocial behavior, it takes time because they need to cognitively control their default preferences that are not consistent with prosocial behavior. In prosocials, the default preference for prosociality is high, and they are able to quickly perform prosocial behavior consistent with it. However, when they do not engage in prosocial behavior, it takes time because they need to cognitively control their default preferences that are not consistent with selfish behavior.

Fig. 2

Results of voxel-based morphometry analysis showing the interaction effect of social value orientation and prosocial behavior. A) Whole-brain analysis reveals that the volume of the right dorsolateral prefrontal cortex (DLPFC) (26, 60, 24) shows an interaction effect between social value orientation and prosocial behavior (P_FWE < 0.05). B) The larger is the volume of the right DLPFC in proselfs, the higher is the level of prosocial behavior. Conversely, the smaller is the volume of the right DLPFC in prosocials, the higher is the level of prosocial behavior. The volume of the right DLPFC is used in the analysis after controlling for age, sex, and total gray matter volume. The blue and red areas represent 95% confidence intervals. SVO = social value orientation.