A recent neuroimaging study in China had romantic couples and pairs of strangers play a simple card game while undergoing functional near-infrared spectroscopy (fNIRS) scans. The results showed that romantic couples achieved higher brain synchronization and used less deception (to win the game) compared to pairs of strangers. The research, published in Brain Sciences, suggests that romantic couples may have a neural advantage in fostering honesty through deeper brain connections.
Interpersonal brain synchronization is a phenomenon where the brain activity of two or more individuals becomes aligned or synchronized during social interactions. This synchronization can be observed using techniques that monitor brain activity, such as electroencephalography (EEG), functional magnetic resonance imaging (fMRI), or fNIRS. It is thought to occur when individuals are engaged in cooperative tasks, effective communication, or shared emotional experiences.
However, studies suggest that when individuals engage in deceptive behavior, the usual brain synchronization that occurs during honest and cooperative interactions may decrease. This is because deception involves cognitive processes like inhibition, conflict monitoring, and effortful control, which can disrupt the natural alignment of brain activity. For example, when one person is trying to deceive another, the brain regions associated with social and emotional alignment may show less synchrony compared to when they are being truthful.
The mental effort required to fabricate information or hide the truth can break down the regular flow of mutual understanding, disrupting brain synchronization. Because of this, some researchers believe that it might be possible to detect deceptive behavior by monitoring brain synchronization between individuals engaged in social interaction.
Study author Chong Shao wanted to explore how the relationship between individuals and their gender influences the level of brain synchronization during a game, as well as how levels of honesty and deception would be associated with these characteristics. The experiment was conducted using fNIRS.
fNIRS is a non-invasive neuroimaging technique that uses near-infrared light to measure brain activity by detecting changes in blood oxygen levels, particularly in the cortical regions. The study focused on the prefrontal cortex and the right temporoparietal junction. The prefrontal cortex is important for engaging in the process of deception, but also for detecting deception. The right temporoparietal junction is a brain region strongly associated with mentalizing ability, which is the ability to attribute mental states such as beliefs, desires, and intentions to oneself and others. Previous studies have also detected activities associated with deception in this area.
The study involved 184 college and undergraduate students, all in male-female dyads. Of these, 146 were romantic couples, and 38 were strangers, all in their early 20s.
In the experimental session, dyads played a card game called “Natural Enemy” (one member of the dyad against the other) while undergoing fNIRS. This card game was developed by the study authors for the experiment, inspired by sender-receiver and rock-paper-scissors games. In the game, one partner (the informer) would see two cards, while the other partner (the guesser) would see only one. One of the cards beats the other (similar to rock-paper-scissors). The informer is then supposed to describe the card the guesser has not seen. After this, the guesser has to choose one of the two cards.
If the guesser chooses the higher card, they win. The informer wins if the guesser chooses the lower card. The informer is free to either honestly describe the card to the guesser or attempt to deceive them. The amount of money each participant received for participation depended on how much they won or lost in this game.
The results showed that romantic couples were less likely to deceive each other compared to strangers. This was reflected not only in their behavior but also in their brain activity. The researchers found that romantic couples exhibited increased brain synchronization in the prefrontal cortex and right temporoparietal junction when they were interacting, especially during moments of potential deception. This synchronization was higher in romantic couples than in stranger pairs.
Interestingly, the researchers found that brain synchronization was negatively correlated with deception rates in romantic couples. In other words, the stronger the brain synchronization between two romantic partners, the less likely they were to deceive each other. This suggests that the brain connections between romantic partners may play a role in promoting honesty and maintaining trust in the relationship.
In contrast, no significant increase in brain synchronization was observed between the stranger pairs. This lack of synchronization may help explain why strangers were more likely to deceive each other than romantic couples. The results also showed that females tended to deceive males more than the other way around, but this pattern held true more for strangers than for couples.
Moreover, when romantic couples did deceive each other, the researchers found that the brain regions involved in these interactions differed based on the gender of the sender. Male senders showed increased synchronization in brain areas linked to mentalizing, or understanding the thoughts and intentions of others, while female senders displayed higher synchronization in areas associated with social processing.
“The result corroborated the lower deception of males and romantic couples in cross-sex interactions. Furthermore, IBS [interpersonal brain synchronization] in the PFC [prefrontal cortex] and rTPJ [right temporoparietal junction] was the underlying dual-brain neural basis for supporting honesty in romantic couples,” the study authors concluded.
The study sheds light on brain activity during deceptive behaviors. However, it should be noted that the pairs of participants played a simple game with very low stakes, and the results might differ with other types of games or when the stakes are higher.
The paper “Increased Interpersonal Brain Synchronization in Romantic Couples Is Associated with Higher Honesty: An fNIRS Hyperscanning Study” was authored by Chong Shao, Xuecheng Zhang, You Wu, Wenhai Zhang, and Binghai Sun.
