The brain is an intricate piece of machinery with billions of neurons that constantly interpret abstract information from the external world. In a recent study published in Nature Neuroscience, researchers from the UK and Switzerland have linked self-control to the interaction between two neuronal networks in the prefrontal cortex. The researchers identified behavioural responses to specific social situations by disrupting the brain using repetitive transcranial magnetic stimulation (rTMS) and then using functional magnetic resonance imaging (fMRI) for mapping correlations between neural networks involved in decision-making and punishment. Independent of each other, the brain imaging and brain stimulation methods are not able to determine causal mechanisms between the prefrontal brain regions. The current study fuses these methodologies to harness their synergy. Paired with fMRI, rTMS not only locates behavioural effects from the disruption of parts of the brain but also finds causal mechanisms in that task-related activity of the disrupted region. The experiment involved disrupting regions associated with complex planning, emotions, and reasoning using rTMS and then having study participants play an ultimatum game. The game is essentially a bargaining problem in which players are given an amount of money to distribute with other players. The proposer offers to split the total with the responder who can then accept or reject this offer. If accepted, the players both receive the bargained amount, and if rejected, neither receives anything. Proposing unbalanced offers is seen as a norm violation in Western culture and was referred to as the baseline for fairness norms. The game was used to test the participants’ ability to reject normally unfair offers under altered circumstances. When players were disrupted on the right side of their head, they were able to judge whether a deal was unfair but were more likely to accept the offer anyway. Compared to the control group the participants seemed unable to resist self-gratification even while they knew it to be anti-social or deviant behaviour. It may be the case that cortical areas that render us unable to feel negative emotions towards what we consider unfair makes us much more likely to accept self-gratification. This would signify that the development and association of these emotions with social interaction is a vital part in delaying self-gratification and allowing cooperation with others.
Self-control is an essential virtue for a society that needs its citizens to be capable of delaying self-gratification in favour of social norms. In philosophy, psychology, and bargaining theory, self-control is necessary for the formation of agreements because agreements involve someone invoking a temporary loss in exchange for future benefit. Society is built upon these types of repeated interactions: the exchange of our resources to coordinate better outcomes. Civilization, to this end, depends on the delay of self-gratification.
But it is not enough for a better outcome to exist to make it real. Rules maintain these interactions, and the formation of rules must be related to some cortical processes. Drawing on neurobiology, the researchers in this study have not only searched for neural networks expected to be involved in allowing delay of self-gratification but also the rudiminentary cognition involved in the formation of social coordination.
The study faces some limitations by relying on the ultimatum game model since it is a specific type of social interaction with strict assumptions that may not be realistic. Even if we accept the model, inferring preferences from observable behaviour can be problematic — our choices may not necessarily reflect our desires.
Hopefully, these researchers’ findings may be used to explain the implications of brain damage for social deviance and to illustrate the therapeutic use of non-invasive rTMS in the treatment of the persistent antisocial and aggressive behaviours found in some types of psychiatric cases.
