Background: Clinical researchers face challenges when trying to quantify diverse processes engaged during social interactions. We report results from two studies, each demonstrating the potential utility of tools for examining processes engaged during social interactions.Method: In the first study, youth (n = 57) used a smartphone-based tool to rate mood and responses to social events. A subset (n = 20) completed the second, functional magnetic resonance imaging study. This second study related anxiety to error-evoked brain responses in two social conditions-while being observed and when alone.We also combined these tools to bridge clinical, social-contextual, and neural levels of measurement.Results: Results from the first study showed an association between negativelyperceived social experiences and a range of negative emotions. In the second study there was a positive correlation during error monitoring between social-anxiety severity and context-specific activation of the pregenual anterior cingulate cortex.Finally, during imaging, the perceived quality of peer interactions as assessed using the smartphone-based tool, interacted with social context to predict levels of activation in the hippocampus and superior frontal gyrus.Conclusions: By improving measurement, enhanced tools may provide new means for studying relationships among anxiety, brain function, and social interactions.