<p>Signaling theory elaborates how communicative patterns and signals, such as facial expressions, have facilitated interactions hence helped social animals survive. Signaling theory suggests that those sending clearer signals, through the face or otherwise, may be more trustworthy communicators. This would apply even to negative emotional signals such as disgust. In contrast, the overgeneralization hypothesis suggests a clear negative facial expression might overgeneralize to have a deleterious effect on judgments of someone’s trustworthiness. We tested this in a study where 64 males and 70 female judges viewed 12 video clips, featuring 6 men and 6 women showing either a macro expression (M = 2.66s duration) or a micro expression (M = 0.34s duration) of disgust, as they spontaneously reacted to a bad-tasting drink. The judges then rated the participants on how trustworthy, authentic believable, and likeable they appeared. A repeated measures MANOVA found all macro expression signal givers to be perceived significantly more trustworthy, authentic, believable, and likeable compared with micro expression signal givers. A significant interaction between length of expression and gender showed when expressing macro expressions, female expressers were perceived equally positive to males, yet when expressing micro expressions, female expressers were perceived significantly less trustworthy, authentic, believable, and likeable than males. This study supports a signaling theory explanation and adds further insight into the role clarity of signals has in signaling theory.</p>