Children and infant animals have virtually no capacity for biological self-regulation; their internal biological states—heart rates, hormone levels, nervous system activity—depend completely on their relationships with caregiving grown-ups. Emotions such as love, fear or anger serve the needs of protecting the self while maintaining essential relationships with parents and other caregivers. Psychological stress is whatever threatens the young creature’s perception of a safe relationship with the adults, because any disruption in the relationship will cause turbulence in the internal milieu.
