The specific aims of this project are to (1) test the mechanisms by which AAIs reduce anxiety, and (2) determine if the anxiolytic effect of social and physical interaction is moderated by level of pre-existing social anxiety. To achieve these aims, 75 adolescents (age 13-17) will undergo a well-validated laboratory-based social evaluative stressor, the Trier Social Stress Task for Children, and be randomly assigned to one of three conditions: 1) no interaction with a dog (control condition), 2) social interaction only (no physical interaction) with a therapy dog; or 3) social interaction plus physical interaction with a therapy dog. Using a multivariate approach, three levels of outcome data will be collected: a) self-reported experience (anxiety), b) autonomic physiology (heart rate), and c) behavioral performance (error rates on mental math task). In addition, the interactions will be videotaped and behavioral coding will be used to explore the specific social behaviors between the participant and the dog that may predict anxiety reduction (such as frequency or type of social referencing or physical contact).