Neural Correlates of Gratitude: Insights from fMRI Studies
Gratitude is a vital aspect of human sociality, valued across religions and moral philosophies. It has been established that gratitude leads to benefits for both mental health and interpersonal relationships. Thus, it is important to elucidate the neurobiological correlates of gratitude, which are only now beginning to be investigated.
Altruism and gratitude are two sides of the same coin. However, until recently it was unclear how altruism from a benefactor translated into gratefulness in the brain of a beneficiary.
On May 7, a new paper, “Decomposing Gratitude: Representation and Integration of Cognitive Antecedents of Gratitude in the Brain,” was published in the Journal of Neuroscience. The latest findings by Xiaolin Zhou and colleagues suggest that the pgACC plays an integrative role in generating gratitude.
Anterior Cingulate Cortex
Investigating Gratitude Through fMRI Studies
To investigate this research question, Zhou et al. designed a socially interactive game that could be played in a brain scanner. During this game, one player could pay a specific sum of money to prevent another player from receiving a painful shock. At various stages of play, both the degree of pain intensity and the cost of preventing an electric shock to another player were manipulated to make it more or less expensive to be altruistic and help someone else avoid pain.
Key Findings from the Study
Notably, the researchers found that being a potential benefactor-who was in a position to be altruistic and relieve someone else's pain at a cost-activated brain regions involved in mentalizing (e.g., temporoparietal junction).
Sometimes, when a player’s pain was relieved, the beneficiary didn’t know that another player had made a sacrifice to stop the electric shock. As would be expected, when a player was aware that his or her pain reduction was the direct result of another player being altruistic, it triggered varying degrees of gratitude. The intensity of someone's gratitude was correlated with the perigenual anterior cingulate cortex (pgACC) lighting up to varying degrees in the fMRI.
Experimental Design and Results
To this end, we conducted an experiment during which we induced gratitude in participants while they underwent functional magnetic resonance imaging. We hypothesized that gratitude ratings would correlate with activity in brain regions associated with moral cognition, value judgment and theory of mind.
The stimuli used to elicit gratitude were drawn from stories of survivors of the Holocaust, as many survivors report being sheltered by strangers or receiving lifesaving food and clothing, and having strong feelings of gratitude for such gifts. The participants were asked to place themselves in the context of the Holocaust and imagine what their own experience would feel like if they received such gifts. For each gift, they rated how grateful they felt.
The results revealed that ratings of gratitude correlated with brain activity in the anterior cingulate cortex and medial prefrontal cortex, in support of our hypotheses. The results provide a window into the brain circuitry for moral cognition and positive emotion that accompanies the experience of benefitting from the goodwill of others.
Brain activity during the reflection period compared to baseline.