In the theory of attachment, Bowlby emphasized the importance of a secure base for a healthy infant-caregiver relationship and ongoing development. This secure base is the primary caregiver who acts as a secure position from which the infant can explore the world (Bowlby, 969. cited in Newman et al., 205). The nature of this secure early relationship influences the development of inner working models, or representations, of the self, other, and relationships. The ideas proposed by John Bowlby were later corroborated by the work of Mary Ainsworth (93-999) with the Strange Situation procedure a laboratory paradigm investigating infant-parent attachment. Ainsworth went on to define patterns of secure and insecure attachment and related these to patterns of emotional interaction that could be identified in the relations between the infant and the carer (Newman et al., 205). For a secure attachment, the infant uses the caregiver as a secure base for exploration. They would experience distress as a result of separation from the caregiver but are able to be comforted upon the caregivers return (Newman et al., 205). There are several kinds of literature that suggest that the formation of a healthy infant-caregiver bond can encourage typical brain development, in particular, the right brain. The right brain is involved in processing social-emotional information, facilitating attachment functions, regulating bodily and affective states (Schore, 994;998. cited in Malekpour, 2007), and controlling vital functions that allow organisms to cope with stress (Wittling & Schweiger, 993). According to Allan Schore, the maturation of the right brain regulatory capacities is dependent on the experience embedded in the attachment relationship between the infant and primary caregiver (Schore, 2000, 205). However, this experience can positively or negatively influence the development of brain structure. Other researchers have expressed that when a caregiver is interacting with their infant (e.g., hugging, holding),
brain networks are activated and strengthened, and firing spreads to associated networks. Also, when the infant is sung to, other networks that allow for sound to be received and interpreted are strengthened (Epstein, 200). Thus, the evidence implies that early social environments directly impact the early maturation of the brain.
Contrarily, an insecure attachment where the healthy and secure bond has been contaminated by fear and neglect creates anxious or avoidant children. It also results in alterations to particular brain regions, especially those implicated in emotional regulation (De Bellis & Kuchibhatla, 2006; Strathearn, 208). This experience-dependent nature of the infant brain has been demonstrated in various studies of groups of children who were exposed to early unusual caregiving environments. McCrory et al (202) revealed that structural and functional abnormalities in cortical and subcortical regions may contribute to subsequent deficits in affect regulation in not only children but also adults who have been exposed to early relational trauma or maltreatment from abusive or neglectful caregiving (McCrory et al., 202). Another study utilizing the PET imaging technique investigated brain activation in post-institutionalised Romanian children and found relatively lower metabolism in a network of areas associated with stress regulation, including the orbitofrontal cortex (Chugani et al., 200) which is involved in the cognitive process of decision-making. This study received further support from event-related potential studies that found cortical hypoactivation in maltreated children when viewing emotional facial expressions of familiar and unfamiliar individuals (e.g., Pollak & Sinha, 2002). Furthermore, hypoactivation of specific regions such as the right-hemisphere frontal, medial temporal, and limbic structures associated with emotion regulation can hinder the integration and connectivity between these areas in children who have suffered attachment-related trauma (Schore, 2009).