Emotion expressions convey valuable information about others’ internal states and likely behaviours. Accurately identifying expressions is critical for social interactions, but so is perceiver confidence when decoding expressions. Even if a perceiver correctly labels an expression, uncertainty may impair appropriate behavioural responses and create uncomfortable interactions. Past research has found that perceivers report greater confidence when identifying emotions displayed by cultural ingroup members, an effect attributed to greater perceptual skill and familiarity with own-culture than other-culture faces. However, the current research (...) presents novel evidence for an ingroup advantage in emotion decoding confidence across arbitrary group boundaries that hold culture constant. In two experiments using different stimulus sets participants not only labeled minimal ingroup expressions more accurately, but did so with greater confidence. These results offer novel evidence that ingroup advantages in emotion decoding confidence stem partly from social-cognitive processes. (shrink)