Expressing emotion is one of the key functions of nonverbal communication. Emotions are affective reactions people have to stimuli in their environment. The way emotions are expressed is influenced by innate action tendencies as well as social and cultural rules for what constitutes appropriate expression. Basic emotions—such as happiness, anger, and fear—tend to be encoded and decoded similarly across cultures, although nonverbal accents give people a within-culture advantage in decoding emotions accurately. Physiological changes to emotion-evoking stimuli are biologically based. Mimicking a facial expression sends signals to the brain that can lead people to experience physiological changes and the corresponding emotion. People also manage their emotional expressions, including exaggerating, masking, and hiding how they feel. Some professions require this type of emotional labor. Skill in expressing, managing, and decoding emotion is both innate and learned. People who possess these skills and are emotionally intelligent have an advantage in personal and professional relationships.