When we see someone change their direction of gaze, we spontaneously follow their eyes because we expect people to look at interesting objects. Bayliss and Tipper (2006) examined the consequences of observing this expectancy being either confirmed or violated by faces producing reliable or unreliable gaze cues. Participants viewed different faces that would consistently look at the target, or consistently look away from the target: The faces that consistently looked towards targets were subsequently chosen as being more trustworthy than the faces that consistently looked away from targets. The current work demonstrates that these gaze contingency effects are only detected when faces create a positive social context by smiling, but not in the negative context when all the faces held angry or neutral expressions. These data suggest that implicit processing of the reward contingencies associated with gaze cues relies on a positive emotional expression to maintain expectations of a favourable outcome of joint attention episodes.