All that meets the eye: The contribution of reward processing and pupil mimicry on pupillary reactions to facial trustworthiness

The present work investigates pupillary reactions induced by exposure to faces with different levels of trustworthiness. Participants’ (N = 69) pupillary changes were recorded while they viewed white male faces with a neutral expression varying on facial trustworthiness. Results suggest that reward processing and pupil mimicry are relevant mechanisms driving participants’ pupil reactions. However, when including both factors in one statistical model, pupil mimicry seems to be a stronger predictor than reward processing of participants’ pupil dilation. Results are discussed in light of pupillometry evidence.