Anxiety sensitivity (AS) refers to the fear of behaviors or sensations associated with the experience of anxiety, and a misinterpretation of such sensations as dangerous. According to David Clark and Aaron Beck anxiety sensitivity is an intolerance of the physical, behavioral, and cognitive symptoms of anxiety because of beliefs that these symptoms have negative physical, social, or psychological consequences. Bodily sensations related to anxiety, such as nausea and palpitations, are mistaken as harmful experiences, causing anxiety or fear to intensify. For example, a person with high anxiety sensitivity may fear the shakes as impending neurological disorder, or may suspect lightheadedness is the result of a brain tumour; conversely, a person with low anxiety sensitivity is likely to identify these as harmless and attach no significance to them. The Anxiety Sensitivity Index attempts to assess anxiety sensitivity.