A child's (or an adult's) nervous system may detect danger or a threat to life when the child enters a new environment or meets a strange person. Cognitively, there is no reason for them to be frightened. But often, even if they understand this, their bodies betray them. Sometimes this betrayal is private; only they are aware that their hearts are beating fast and contracting with such force that they start to sway. For others, the responses are more overt. They may tremble. Their faces may flush, or perspiration may pour from their hands and forehead. Still others may become pale and dizzy and feel precipitously faint.

Dr. Peter Levine, who has worked with trauma survivors for twenty-five years, says the single most important factor he has learned in uncovering the mystery of human trauma is what happens during and after the freezing response. He describes an impala being chased by a cheetah. The second the cheetah pounces on the young impala, the animal goes limp. The impala isn’t playing dead, she has “instinctively entered an altered state of consciousness, shared by all mammals when death appears imminent.” (Levine and Frederick, Waking the Tiger, p. 16) The impala becomes instantly immobile. However, if the impala escapes, what she does immediately thereafter is vitally important. She shakes and quivers every part of her body, clearing the traumatic energy she has accumulated.