Figure 1

Overview of the task and trial structure. (A) At the beginning of each trial, three letters (i.e., A–C) with different payoffs (i.e., 20, 25, and 30) were presented. After one of these letters appeared randomly, the sender chose an option to send a message about this letter to the receiver and earned the payoff associated with his/her chosen option. (B) According to the associated payoff for the assigned letter, there were three conditions, i.e., HI, LDI and HDI. Then, the sender’s actions were divided into four categories, i.e., honest, full lying, partial lying and disadvantageous lying, depicted by green, red, yellow and gray, respectively. The sender’s payoff depended only on his/her chosen option, and the receiver’s payoff was dependent on whether the sender sent the true message.