Emotional expressions in psychology are observable verbal and nonverbal behaviors that communicate an internal emotional or affective state. Examples of emotional expression are facial movements such as smiling or scowling, or behaviors like crying or laughing. Emotional expressions can occur with or without self-awareness. Presumably, individuals have conscious control of their emotional expressions; however, they need not have conscious awareness of their emotional or affective state in order to express emotion. Over the last 200 years, researchers have proposed different and often competing models explaining emotion and emotional expression, going all the way back to Charles Darwin. However, all theorists in emotion agree that all normal, functioning humans experience and express emotions with their voices, faces, and bodies.