The early stage of infancy is greatly characterized by rapid and significant brain growth. This growth facilitates the development of crucial neurodevelopmental capacities underlying advanced psychological and emotional well-being (Dobbing & Sands, 1973). Some accounts of early brain development argue that this growth majorly occurs within a biological context. However, others have contended that interpersonal context where structural and functional networks are shaped by the nature and quality of early caregiver-infant interactions (Newman et al., 2015) is just as important for typical early brain development. This caregiver-infant relationship has been highlighted for its role in early child development, it has also been the basis for the attachment theory, proposed by John Bowlby (1958). The attachment theory posits an integrative framework of human development, where development transpires in the context of our early relationships (Newman et al., 2015). This attachment system is viewed as an innate, homeostatic system that provides the regulation of proximity-seeking and contact-maintaining behaviours in infancy (Bowlby, 1969. cited in Newman et al., 2015). Any disruptions to this early caregiver-infant relationship can result in alterations to neurological and social aspects of early development. Much of the early work of John Bowlby borrows from the ideas of Sigmund Freud and has been further expanded by Mary Ainsworth. The purpose of this essay is to explore the connection between attachment and early neurological development.
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, 1969. cited in Newman et al., 2015). 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 (1913-1999) 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., 2015). 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 caregiver’s return (Newman et al., 2015). 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, 1994;1998. cited in Malekpour, 2007), and controlling vital functions that allow organisms to cope with stress (Wittling & Schweiger, 1993). 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, 2015). 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, 2001). 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, 2018). 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 (2012) 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., 2012). 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., 2001) 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).
Moreover, a stressful and unideal early environment can also contribute to physiological dysregulation of an individual’s stress regulation systems, especially the hypothalamus-pituitary-adrenal (HPA axis) (Kinlein et al., 2015; Strathearn, 2018). The dysregulation of the HPA axis results in impaired stress regulation in maltreated populations as feedback loops regulating glucocorticoid hormones are disturbed by non-typical or adverse early attachment interactions (Burke et al., 2005), thus, resulting in individuals becoming highly sensitive to stress (Kaufman & Charney, 2001) which further increases vulnerability to later psychiatric conditions in later childhood and adulthood (e.g., mood and anxiety disorders) (Kinlein et al., 2015; Penza et al., 2003).
In summation, the previously proposed neurobiological findings imply that impaired early caregiving and trauma, during infancy, a crucial stage of brain development, can have long-term consequences on neurological development, and social functioning and increase the risk of psychopathology in later childhood and adult life. Thus, the formation of a healthy and interactive bond with the infant is crucial.