The three factors of emotions theory states that a person's emotional state can be described as a point in three-dimensional space. The three dimensions of this space are those factors of emotion. Psychologists arrived at the division of these three factors by observing nonverbal behavior. Nonverbal behavior is special in that it cannot be turned off -- it is continuously communicating and transferring messages about the user's emotional state. Through categorizing aspects of nonverbal behavior, psychologists were able to arrive at a clear set of "emotional axes" on which a three-dimensional space could be constructed.
The pleasure/displeasure axis of the three factors of emotion theory describes whether a person is experiencing a subjectively positive or subjectively negative emotional state. You can infer where a person is on this factor by observing specific aspects of his facial expression. Smiles and the contraction of the muscles around the eyes are associated with pleasure. Frowns, the widening of the eyes and extreme movements of the eyebrows indicate displeasure.
Dominance and submissiveness make up the two ends of the second axis of the three factor theory of emotions. Dominance refers to an individual's perceived ability to control her condition, while submissiveness refers to the opposite (feelings of lack of control). In this theory of emotion, dominance and submissiveness are not exclusively associated with interpersonal situations; dominance and submissiveness also exist in situations in which people are not physically present. Posture is the most obvious indicator of a person's point on the dominance/submissiveness axis.
Arousal is the last axis in the three factor theory of emotion. Arousal refers to the emotional "energy" of the person. An aroused person is likely physically active or restless, whereas someone who is low in arousal is calmer and more inactive. A person's level of arousal places him at a specific point on this axis; for example, fear and anger tend to be associated with higher degrees of arousal and will be more toward the positive end of this axis.