1) There are four main people styles - analytical, amiables, expressives, and drivers - which are determined by levels of assertiveness and responsiveness.
2) Under stress, people tend to develop "backup styles" of behavior to relieve excess stress. For example, expressives may attack, drivers may become autocratic, amiables may comply, and analyticals may avoid conflict.
3) If stress continues and is not relieved, people may act in ways totally opposite to their primary style, known as their "secondary backup style." Understanding different styles helps improve relationships.