Altruistic and self-serving goals modulate behavioral and neural responses in deception

Abstract

People tell lies not only for their own self-interests but sometimes also to help others. Little is known about the ways in which different types of goals modulate behaviors and neural responses in deception. The present study investigated the neural processes associated with spontaneous deception that occurs with altruistic reasons (i.e. the money would be donated to charity), self-serving reasons (i.e. the participant receives all of the money) and mixed goals (i.e. the money would be equally split between the participant and the charity). Altruistic motivation for deception reduced the intensity of moral conflict and the subsequent mental cost of resolving this conflict, reflected by a smaller N2-P3 effect in the purely altruistic condition. When making decisions about whether to lie, self-interest was a stronger motivator than others' interests, and the participants tended to lie more for themselves than for others. When the lie could be mutually beneficial for both of the self and others, the participants tended to lie even when they knew that they could be easily caught, but they actually lied for their own self-interest rather than for altruistic reasons. These findings shed light on the neural basis of 'good lies' and decision-making in mutually beneficial situations.

Keywords: ERPs; altruistic; deception; moral conflict; self-serving.

Fig. 1.

Task sequence. Participants do a coin-flip guessing task. In the NoOP trials, participants were instructed to record their prediction about the upcoming coin flip when the word ‘Press’ appeared on the screen by pressing a button labeled ‘H’ if they predicted ‘head’ and a button labeled ‘T’ if they predicted ‘tail’. In the Op trials, participants made their predictions privately: instead of the ‘Head’ and ‘Tail’ in the NoOP trials, the word ‘Random’ would appear and the participants would press the ‘R’ key to indicate they finished their prediction. The ERPs were locked to the outcome cue screen (marked with a red box).

Fig. 2.

Accuracy rate per group per condition (Real: real accuracy in the NoOp condition; NoOP: reported accuracy in the NoOp condition; Op: reported accuracy in the Op condition) (mean ± s.e).

Fig. 3.

(A) Grand average of N2 at Fz. (B) The difference wave of Op–NoOP and the topographies of the difference wave between 250 and 300 ms. (C) Grand average of P3 at CPz. (D) The difference wave of Op–NoOP and the topographies of the difference wave between 400 and 450 ms.

Fig. 4.

Correlation between ERP components and accuracy rates. The horizontal axis is the reported accuracy of Op–NoOp(0–1) and the longitudinal axis is the mean amplidtude of Op–NoOp (µV). (A) N2_(PS_Op > PS_NoOp) and accuracy_(PS_Op > PS_NoOp); (B) N2_(mixed_Op > mixed_NoOp) and accuracy_(mixed_Op > mixed_NoOp); (C) P3_(PS_Op > PS_NoOp) and accuracy_(PS_Op > PS_NoOp); (D) P3_(mixed_Op > mixed_NoOp) and accuracy_(mixed_Op > mixed_NoOp).