Infant-directed registers are emotion communication, conveying feelings and intentions to infants and toddlers that may facilitate and modulate attention and language learning. As infants are attracted to emotion, it is essential to understand how infants process emotional information. This study used an infant-controlled habituation paradigm to examine how 7- to 15-month-old infants discriminate changes in visual emotion, auditory emotion, or visual+auditory emotion after being habituated to a bimodal emotion display. The purpose of this study was to examine which modality (facial emotion; vocal emotion) was more salient for infants to discriminate emotions in the context of bimodal stimulation. Infants were habituated to happy audiovisual displays then received four test trials, during which neither source of emotion information was changed (control), just the auditory emotion was changed, just the visual emotion was changed, or both sources of emotion information were changed. It was predicted that infants would show the greatest recovery of attention to a change in visual emotion than when only visual information was changed, but less than when both auditory and visual information were changed. However, the results showed that infants were equally sensitive to all three types of emotion change. These results are discussed in terms of concurrent conceptualizations of how emotion processing is related to negative bias and experience with two emotions. / Master of Science / When we interact with infants, we convey feelings and intentions to infants that may facilitate and modulate attention and language learning. As infants are attracted to emotions, it is essential that we understand how infants process emotional information. While previous studies have shown that infants are capable of discriminating different kinds of emotions, no known study has been done to examine whether infants would be more sensitive to a change in facial expression or in vocal expression when they experience both facial and vocal expressions together. To examine this, infants were habituated to happy audiovisual displays. Infants then watched four audiovisual displays that were 1) the same happy audiovisual display, 2) audiovisual display with happy face and fearful voice, 3) audiovisual display with fearful face and happy voice, and 4) audiovisual display with fearful face and fearful voice. It was expected that infants would look longer when facial expression was changed than when vocal expression was change, but less than when both facial and vocal expressions were changed. However, the results showed that infants were equally sensitive to a change in facial expression, vocal expression, and both facial and vocal expressions.