Experiencing stress is a common occurrence in daily life. The types of stressors humans encounter can vary greatly from naturalistic physical stressors to traumatic life stress. Stress has a negative impact on a variety of physical and psychological health outcomes. One important cognitive mechanism that is impacted by stress is working memory. Working memory is responsible for the control of executive attention and as such is related to important higher order cognitive processes including reading comprehension, novel and fluid reasoning, and complex learning. Given the role of working memory in these important higher order cognitive processes understanding factors that may result in impairments in working memory is important. Prior studies have identified two possible mechanisms, cortisol and intrusive thoughts, that are responsible for the impairments seen in working memory that result from stress. However, no single study has examined these two possible mechanisms at the same time. Additionally, it is possible that different types of stressors may involve different mechanism. The current study will examine cortisol and intrusive thoughts prior to and following a physical and psychological stressor. Sixty undergraduates from Nova Southeastern University will be recruited for the study. Participants will be assigned to either the physical or the psychological stressor condition. During a baseline session participants will complete a control version of the stressor task and then a working memory task with measures of intrusive thoughts and cortisol. During a second session participants will complete the stressor task, physical or psychological depending on condition, followed by a working memory task. Measures of measures of cortisol and intrusive thoughts will be made during the working memory task. This study will allow for a better understanding of how stress impacts working memory and will allow for the development of interventions designed to alleviate or prevent stress related working memory impairments.