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With the advent of functional magnetic resonance imaging (fMRI), it is now possible to evaluate brain activation and to isolate structures that may be involved in social perception Hemispheric Effects While photographs have been frequently studied to examine a participant's interpretation of facial expressions, social communication occurs in a dynamic and fluid setting. The use of videotaped vignettes that convey social interactions may be sensitive to the participant's ability to understand context as well as changing situations. Using fMRI, increased activation was found in the frontal-cingulate-parietal connections when faces which were morphed from a neutral emotion to fear or anger were viewed Key Words Right hemisphere ؒ Social interactions ؒ Adults ؒ Functional magnetic resonance imaging Abstract Objective: The main purpose of this study was to evaluate whole-brain and hemispheric activation in normal adult volunteers to videos depicting positive and negative social encounters. There are few studies that have utilized dynamic social stimuli to evaluate brain activation. Method: Twenty young adults viewed videotaped vignettes during an functional magnetic resonance imaging procedure. The vignettes included positive and negative interaction scenes of social encounters. Results: Significant right greater than left activation for positive and negative conditions was found for the social interaction videos in the amygdaloid complex, the inferior frontal gyrus, the fusiform gyrus, and the temporal gyri (p ! 0.0001). Conclusion: These findings support the hypothesis that the regions of the right hemisphere are more active in the interpretation of social information processing than those regions in the left hemisphere. This study is a first step in understanding processing of dynamic stimuli using ecologically appropriate stimuli that approximate the realtime social processing that is appropriate for use with populations who experience significant social problems