Scientists can determine within seconds whether a person is being deceived by a peer, based on shared neural activity across distinct brain regions.
Why do people believe lies? The answer may lie in how our brains process social connections and rewards. Recent research led by Yingjie Liu at North China University of Science and Technology suggests that our willingness to believe false information depends not only on what is being said but also on who is saying it.
By examining how people interpret messages from friends versus strangers, the study reveals that trust, emotional bonds, and the promise of potential rewards all play crucial roles in shaping whether we accept or reject a lie.
According to their JNeurosci publication, the research team used neuroimaging to study 66 healthy participants who interacted through computer screens while seated across from each other. When the exchange of information resulted in a positive outcome for both participants, it was labeled a “gain,” while information that produced a negative outcome was categorized as a “loss.”
Contributing author Rui Huang says, “The key reason we chose ‘gain’ and ‘loss’ contexts is that they illustrate how people adjust decision-making in response to potential rewards or punishments.”
Brain Activity and Belief in Lies
Participants believed lies more frequently in “gain” contexts, which was linked to activity in brain regions involved with risk evaluation, reward, and understanding intention.
Notably, when the deceiver was considered a friend, the two shared brain activity that varied based on context: “Gain” contexts increased synchrony in a reward-related brain region, while “loss” contexts increased synchrony in a risk evaluation region. The researchers could even use this shared brain activity between friendly pairs to predict whether a person would be successfully deceived.
According to the researchers, this work suggests that people may be more likely to believe lies when they promise the potential of a “gain” and points to brain activity involved in social information processing between friends that may make truth evaluations less accurate.
Reference: “Forewarned Is Forearmed: The Single- and Dual-Brain Mechanisms in Detectors from Dyads of Varying Social Distance during Deceptive Outcome Evaluation” by Rui Huang, Xiaowei Gao, Chenyu Zhang, Jingyue Liu, Ye Zhang, Yifei Zhong, Yunen Chen, He Wang, Xing Wei and Yingjie Liu, 21 October 2025, Journal of Neuroscience.
DOI: 10.1523/JNEUROSCI.2129-24.2025
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