There are several theories that attempt to explain the underlying mechanisms of emotions: 1. The James-Lange theory suggests that physiological arousal causes emotional experience. We know we feel sad because we cry. 2. In contrast, cognitive theories emphasize that we appraise situations mentally which then leads to emotions and physiological responses. We recognize emotions based on our evaluations. 3. Later theories integrated both physiological and cognitive elements. Schachter's two-factor theory proposed that arousal alone does not determine the quality of emotion, but rather our cognitive appraisal of the situation.