Modern eye-tracking has advanced research on gaze behavior in realistic social interactions. It was already shown that blinking frequency and duration both increase during deception (George et al., 2017), in states of joy (Moharana et al., 2021), or in mutual gazing (Cakir & Huckauf, 2023). Card games provide an ideal framework to study social interactions by offering both experimental control and ecological validity, particularly regarding bluffing and confidence in winning. To further investigate factors that may influence gaze patterns in these settings, we introduce a condition involving stakes as monetary incentives, which should enhance engagement (Camerer & Hogarth, 1999). As the primary contribution of this study, we developed a paradigm to examine whether and how bluffing and confidence in winning can shape gaze signatures and how these signatures are modulated by monetary incentives. Furthermore, it is hypothesized that blink frequency and duration are expected to increase during both bluffing and confidence in winning.

The game is played by two participants face-to-face on a touch-screen table to ensure standardization. Participants play 64 trials within 4 blocks, two with and two without monetary incentives. The cards are being distributed selectively to ensure confidence in winning or in losing, respectively, and to vary the necessity to bluff. In the incentive condition, participants receive lottery tickets for each win, increasing their chance of winning monetary prizes. This within-subject design shall be executed with 40 participants. Eye movements and blink behavior are tracked using eye-tracking glasses (Pupil Labs Neon).