Defensive behavior occurs when an individual reacts to a perceived threat and begins using self-protective measures. Defensive behaviors come in a variety of forms, but typically the person becomes agitated, louder and more animated.
Defensive behaviors stem from primitive defense mechanisms that helped human ancestors survive, both physically and psychologically. When faced with a threat, the drive to fight or flee kicks in, and when there is no place to go, it is natural for a person to want to fight. By displaying defensive behaviors, an individual is preparing for the fight, be it a physical fight or a mental one.
When a person is exhibiting defensive behaviors, he is agitated and has adrenaline pumping through his body. He becomes louder and tries to appear bigger. This is a natural attempt to intimidate the threat.
The primal urge to resort to defensive behaviors also occurs when someone becomes frustrated and has difficulty verbalizing thoughts and feelings. When a young child throws a temper tantrum, it is often because he is angry and cannot figure out another way to express the emotion. The temper tantrum eases stress and becomes an outlet for the adrenaline. A person is often not aware he is exhibiting these behaviors.