First, attachment ensures the infant remain in the proximity of the caregiver to procure resources for survival and protection. Second, attachment “quality programs” the brain. This programming impacts immediate behaviors, as well as behaviors that emerge later in development.
We have known for decades that childhood experiences interact with genetics to change the structure of the brain and cause behavioral change.1 These early life experiences can dramatically alter the number of specialized communication cells within the brain (neurons), and these experiences can then increase or decrease the complexity of the neurons (dendritic branches) and the number of communication sites between them (synapses). The effects of this experience-based sculpting of the brain have profound effects on how the brain functions. In particular, they can determine how emotional centers of the brain communicate with the cortex and its higher functioning to determine our personality, our choices, and how we approach the world. This flexible, experience-based tuning of the brain’s development enables many parenting styles and relationships to produce children who grow into productive, law-abiding citizens that contribute to society. Aberrant experiences, including abuse and neglect from the caregiver, however, can hijack this experience-based system, leading to emotional and cognitive deficits and a view of the world as a dangerous place. These early life traumas go beyond the normal programming of the brain and initiate a pathway to pathology, which can often have a delayed expression until the child approaches periadolescence. Since early life abuse can be associated with brain damage from prenatal and postnatal (that is, via lactation) drug and alcohol abuse,2 the effects of child abuse can be comorbid with additional difficulties. Decades ago, we attributed these deficits to psychological problems as though there was no physical manifestation of the problems, but we now know better—the structure and functioning of the brain contribute to these behavioral traits. This Article reviews the child abuse and neglect neuroscience literature presented within the framework of attachment, because most abuse is from the caregiver. Attachment has two basic functions: (1) Attachment ensures the child remain in proximity of the caregiver, and (2) attachment programs the lifelong structure and function of the brain. Importantly, within this framework the effects of early life abuse can be expressed differently at different ages, with short- and long-term effects showing distinct patterns and the most dramatic effects delayed until later life.3
Furthermore, children tolerate considerable abuse while remaining strongly attached to an abusive caretaker. It appears that selection pressure and evolution have produced an attachment system that ensures the infant attaches to the caregiver regardless of the quality of caregiving received.
It is thought that the chronic stress of chaotic homes, divorce, abuse, and other stressors produce prolonged stress responses that are particularly damaging to children. One mechanism that can reduce stress hormone release is social buffering, whereby an attachment figure (or, at later stages of development, a trusted partner) can greatly attenuate the release of stress hormones. Indeed, the attachment figure is a strong social buffering stimulus in children, although this system appears compromised in some abused children. Social buffering can protect a child from the damaging effects of stress. The role of the attachment figure as a regulator of the child’s stress response for social buffering is related to the role of the mother as a “hidden regulator” of physiological functions discussed in Part II.24