This study will evaluate the effects of Mindfulness-Based Stress Reduction (MBSR) on physiological reactivity. This study will focus on individuals with anxiety who will participate in an 8-week MBSR class. The investigators will test participants' reactivity to both predictable and unpredictable stimuli before and after the class to understand the physiological changes that may occur after to the intervention. Secondary measures include psychometric instruments and a delay discounting task.