Study reveals part of brain necessary for helping others
Melanie May | 28 May 2024 | News
A study of people with brain damage has revealed that willingness to help others is governed by a specific brain region.
The study, published in Nature Human Behaviour, was carried out by researchers at the University of Birmingham and the University of Oxford, and shows for the first time how a region called the ventromedial prefrontal cortex (vmPFC) has a critical role in ‘prosocial’ behaviours.
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Lead author Professor Patricia Lockwood said:
“Prosocial behaviours are essential for addressing global challenges. Yet helping others is often effortful and humans are averse to effort. Understanding how effortful helping decisions are processed in the brain is extremely important.”
The study
In the study, the researchers focused on the vmPFC, a region at the front of the brain, which is known to be important for decision-making and other executive functions. Previous studies using magnetic resonance imaging (MRI scanning) have linked the vmPFC to choices that involve a trade-off between the rewards available and the effort required to obtain rewards. However, this technique cannot show whether a part of the brain is essential for these functions.
Three groups of participants were recruited for the study. 25 patients had vmPFC damage, 15 patients had damage elsewhere in the brain, and 40 people were healthy age and gender-matched control participants.
Each attended an experiment where they met another person anonymously. They then completed a decision-making task that measured how willing they were to exert physical effort (squeezing a grip force device) to earn rewards (bonus money) for themselves and for the other person.
By enabling participants to meet but not see the person they were ‘working’ for in advance, researchers were able to convey the sense that participants’ efforts would have real consequences, but hide any information about the other person that could affect decision-making.
Each choice the participants made varied in how much bonus money for them or the other person was available, and how much force they would have to exert to obtain the reward. This allowed the researchers to measure the impact of reward and effort separately, and to use advanced mathematical modelling to precisely quantify people’s motivation.
vmPFC region necessary for motivation to help others
The results of the study clearly showed that the vmPFC was necessary for motivation to help others. Patients with vmPFC damage were less willing to choose to help others, exerted less force on even after they did decide to help, and earned less money to help others compared to the control groups.
In a further step, the researchers used a technique called lesion symptom mapping which enabled them to identify even more specific subregions of the vmPFC where damage made people particularly antisocial and unwilling to exert effort for the other person. However, they also found that damage to a nearby but different subregion made people relatively more willing to help.
Co-lead author Dr Jo Cutler said:
“As well as better understanding prosocial motivation, this study could also help us to develop new treatments for clinical disorders such as psychopathy, where understanding the underlying neural mechanisms can give us new insights into how to treat these conditions.”
Professor Lockwood added:
“This region of the brain is particularly interesting because we know that it undergoes late development in teenagers, and also changes as we get older. It will be really interesting to see whether this area of the brain can also be influenced by education – can we learn to be better at helping others?”
Link between gut microbiome & social decision-making
More recent research claims to have found a link between our gut microbiome and social decision-making.
Published in PNAS Nexus in May, researchers tested the causal effects of a seven-week dietary intervention versus a placebo on altruistic social punishment behaviour in an ultimatum game.
Results showed that the intervention increased participants’ willingness to forgo a monetary payoff when treated unfairly. The change in social decision-making was related to changes in fasting-state serum levels of the dopamine-precursor tyrosine, which the researchers say suggests a potential link between gut microbiota and brain behaviour.
About Melanie May
Melanie May is a journalist and copywriter specialising in writing both for and about the charity and marketing services sectors since 2001. She can be reached via thepurplepim.com.