First of all, what exactly do we mean by "emotion"? There is much disagreement on this, but one of the most useful definitions, by psychologist Magda Arnold, draws a careful distinction between states and behaviors. In Arnold's theory emotional experience proceeds in three steps: (1) Perception and appraisal (external stimulus is perceived and judged good, bad, useful. harmful, etc., mostly based on learned associations); (2) Emotion (internal state of arousal or "feeling" arises, involving physiological effects); then (3) Action (specific behavior such as approach, avoidance, attack, or feeding, depending on emotional intensity, learned behavioral patterns, and other motivations simultaneously present). In this view emotion is an internal state, not a behavior or a perception of external reality.