The Impact of Cognitive Effort on Prosocial Choices: an EEG study

Prosocial behaviour is a fascinating and complex social construct, and the degree of prosocial choices can be influenced by several factors such as social distance between the individuals as well as empathic abilities. Specifically, real life prosocial actions always come with a certain amount of effort required to the social decision maker, but this aspect has been often neglected in most studies. Previous literature exploring this variable usually adopted money both as a reward and as a cost for being prosocial, thus very little is known about other types of effort.
To address this gap, in our study we focused on exploring the impact of cognitive effort on prosocial choices. We developed a new social decision-making paradigm, where participants had to decide whether to make or not a cognitive effort to reward themselves or another person. The reward at stake was a discount on the time spent on the experimental activity. Together with behavioural data, we also collected EEG data to explore with high temporal resolution the neural dynamics of three phases characterizing social decision making: Options evaluation, Choice, and Feedback processing.
Our results showed that participants significantly reduced their prosocial choices when a cognitive effort was required to reward another individual with respect to when no effort was required. At neural level, we found different processing patterns in the temporal dynamics of neural activity in each decision-making phase. Moreover, we observed frequency-specific differences in connectivity between cortical hubs when a prosocial choice was computed with or without effort. Our findings suggest that prosocial behaviours are processed across multiple brain regions and that their synchrony patterns change as a function of the effort required.