Anger is part of the fight/flight brain response to the perceived threat of pain. When a person makes the cognitive choice to take action to immediately [S]top the threatening/painful behavior of another (person or organization, or any outside force) anger (as opposed to fear) becomes the predominant feeling, with behavioral, cognitive and physiological correlates. In the animal kingdom, when physically threatened, animals will make loud sounds, attempt to look physically larger, bare their teeth, and stare. Humans behave in a similar manner when a perception of potential pain occurs, and the decision to oppose (rather than flee) occurs. Anger is a behavioral pattern designed to communicate "Stop your behavior immediately, it is harmful or threatening- If you don't, violence towards you may follow." Rarely (if ever) does a physical altercation occur without the prior expression of anger by at least one of the participants.