Telling the truth or lying for one's own benefit: social neuroscience and neuroimaging together to show the brain mechanisms of moral choices

A study conducted at the Santa Lucia IRCCS Foundation in collaboration with Sapienza University of Rome investigated the brain's reactions to moral choices: not everyone behaves in the same way

Please note: singular 'they' was used as per Sapienza and international guidelines.


A new study conducted at the Laboratory of Social and Cognitive Neuroscience of the Santa Lucia IRCCS Foundation in collaboration with the Department of Psychology of Sapienza University of Rome and the Laboratory of Neuroimaging of the Santa Lucia IRCCS Foundation has revealed that dishonest choices made during social interactions involve certain areas of the brain, which can be detected through the Functional Magnetic Resonance Imaging technique.

Through fMRI, it was also possible to detect differences in brain activation when participants decided whether or not to lie when their reputation might be at risk.

The study, published in the journal Communications Biology, involved 34 healthy people between the ages of 20 and 46 and used a simple game combined with the possibility of earning a cash prize using functional magnetic resonance imaging. This non-invasive technology analyses brain activity in real time by measuring blood flow in various brain areas.

The card game involved interaction between two players: the player outside the fMRI had to attempt to draw the winning card from two possible ones without being able to verify the outcome of their choice. On the other hand, the participant inside the fMRI had the task of observing and communicating the outcome of the game. They could then decide whether to tell the truth or to lie to change the outcome of the game (e.g. by winning the game when the other should have won - by performing a selfish lie).

The participant in the fMRI scan was aware that in half of the cases, the playing partner would not be able to know whether they had lied or not (reputation not at risk), while in the other half, they would be able to know whether they had lied (reputation at risk).

"The results," say Valerio Santangelo and Lennie Dupont, researchers from the Laboratory of Neuroimaging of the Santa Lucia IRCCS Foundation ", show that dishonest decisions are associated with increased activity in a cortico-subcortical circuit that includes the bilateral anterior cingulate (ACC), anterior insula (AI), left dorsolateral prefrontal, supplementary motor area and right caudate nucleus."

As expected, people tend to decrease the number of selfish lies during the reputation-at-risk condition. Neuroimaging showed that selfish lies during the reputation-at-risk condition were linked to increased connectivity between the bilateral anterior cingulate cortex and the left anterior insula. These two brain regions are strongly implicated in emotional processing and cognitive control.

The research team also showed that this brain activation is not the same for all participants but varies according to personality traits.

Maria Serena Panasiti, a clinical neuroscientist involved in the study and winner of a 'Young Researchers' project of the Italian Ministry of Health on the clinical implications of moral decisions, says: "In particular, more manipulative individuals show less involvement of the anterior cingulate during lying for their own benefit, but greater involvement during truth for the benefit of others. That highlights the need for cognitive control only when the decision conflicts with one's goals, in this case, manipulating others for one's own benefit".

Salvatore Maria Aglioti, study coordinator, adds: "Our research provides important insights into the neural basis of dishonest decisions during social interactions. Understanding these mechanisms could help develop strategies to promote more ethical and responsible behaviour in different social contexts".



Reputation risk during dishonest social decision-making modulates anterior insular and cingulate cortex activity and connectivity - L Dupont, V Santangelo, RT Azevedo, MS Panasiti, SM Aglioti - Communications Biology 2023 


Further Information

Maria Serena Panasiti
Department of Psychology


Thursday, 18 May 2023

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