Neural correlates of second-order verbal deception: a functional near-infrared spectroscopy (fNIRS) study

The present study focused on neural correlates underlying second-order deception. In first-order deception, the recipient of deception is unaware of the deceiver's deceptive intention. However, during second-order deception, the recipient is fully aware of the deceiver's deceptive intention and thus the deceiver needs to use both lies and truths to deceive the recipient. Using the functional near-infrared spectroscopy (fNIRS) methodology and a naturalistic interactive game, we found that second-order deception elicited significantly greater [oxy-Hb] changes in the prefrontal cortex (the right superior frontal gyrus (SFG), BA6) than the non-deceptive control condition. This finding suggests that second-order deception, like first-order deception, engages specifically the cortical regions associated with the planning of complex actions and goal processing. We also found that lying to deceive produced greater neural activities in the right middle frontal gyrus than truth-telling to deceive. This suggests that although both actions serve deceptive purposes, making a false statement contradicting the true state of affairs still requires more executive control and thus greater neural responses in the cortical regions associated with this function. In addition, we found that the successful deception produced greater neural activities in a broad area of the prefrontal frontal cortex than failure to deceive, indicating the involvement of the cortical reward system during second-order deception. Further, failure of truth-telling to deceive produced greater neural responses in the right SFG than failure of lying to deceive. The present findings taken together suggest that second-order deception engages both the cortical executive and reward systems.