1. General Considerations
According to attachment theory (developed by Mary Ainsworth and John Bowlby), every child is born with an innate attachment behavioral system. The biological function of this system is to enhance the chances of survival through proximity seeking, particularly in times of distress and/or need. Although (almost) all children become attached to one or several significant others – mostly caregiver(s) -, the quality of attachment can differ considerably between individuals. Such inter-individual differences emerge because there is a psychological correlate of attachment behavior, namely a felt sense of security.
If proximity seeking attempts are successful, a child learns that attachment figures are available in times of need, a pattern that supports the development of a secure attachment orientation. If proximity seeking attempts under stress do not succeed, however, the child will develop an insecure attachment orientation. The latter can either be avoidant in case of consistently unavailable / unresponsive attachment figures (also referred to as de-activating secondary attachment strategy), or anxious (ambivalent / resistant) in case of unpredictable / unreliable attachment figures (hyper-activating secondary attachment strategy). All above attachment orientations / classifications are summarized as organized. In case of more severe neglect or abuse, a fourth attachment orientation called disorganized has furthermore been proposed, the latter being characterized by a breakdown of organized strategies.
Attachment theory postulates that such attachment patterns in early infancy and childhood become increasingly cognitively encoded during later development (by means of so-called internal working models, or IWMs, of attachment), remain rather stable across the life span, and influence many social emotional behaviors in childhood, adolescence, and adulthood (see also here). The plot thickens that attachment can even be transmitted from one generation to the next, and that it not only influences directly attachment-related processes, but (almost) all social interactions between people.
Recently, however, some of the core assumptions of attachment theory regarding its emergence during development, stability, mechanism of intergenerational transmission, and cross-cultural validity have been challenged (e.g. see here). In my opinion, it will therefore be important to provide more empirical data using social neuroscience methods in the future, ideally applying longitudinal research designs within large(r) participant samples. Please refer to my blog post on “21st Century Attachment Theory and Research: Embracing a Social Neuroscience Approach” and the NAMA page for further reading.
Finally, besides being specifically focused on describing inter-individual differences in attachment according to a distinction between organized secure versus insecure (avoidant & anxious) and disorganized attachment, there are many related concepts in the literature. These concepts concern associated measures in the context of caregiving and parent-child interaction, for example, parental sensitivity, reflective functioning, behavioral reciprocity, etc., and thus highlight the tight interplay between attachment and caregiving.
2. Additional Considerations
2.1. Attachment as a Meaningful Adaptation to the Environment
Please note that inter-individual differences in attachment represent specific adaptations to the environment within which attachment was originally formed. Although it is generally understood that secure attachment is most beneficial for social and emotional development (i.e. social emotional competence), caution is advised in labeling attachment insecurities – and their associated modulations of behavioral, biological, and brain responses – as inferior or detrimental. If so, why would so many of us (up to 50%) be insecurely attached? All (organized) attachment styles / classifications represent meaningful and necessary adaptations to the given environment within which they were formed as they (at least partially) ensure closeness to an attachment figure – the primary function of the attachment system.
According to Social Defense Theory, attachment insecurities may even represent specific advantages on the group level that could compensate possible disadvantages of single individuals by providing the overall group with crucial information on an emerging threat and on how to escape from the latter (for example, see here).
Nonetheless, organized insecure (as well as disorganized) attachment orientations / classifications constitute risk factors for the emergence of mental and physical health issues if the associated secondary attachment strategies are employed chronically and out of context, and/or if there is a complete lack of strategies altogether.
2.2 Cultural Differences in Attachment
It is also important to keep in mind that attachment theory was developed in a western, educated, industrialized, rich, democratic – in short WEIRD – cultural context, and that most research is still performed on WEIRD culture participants / with a WEIRD lens. More cross-cultural research therefore is crucially needed to further extend and specify attachment theory and the emerging applied attachment research – including our functional neuro-anatomical model of human attachment (NAMA) -, on many levels. As nicely put by Rothbaum et al. (2000), “an awareness of different conceptions of attachment would clarify that relationships in other cultures are not inferior but instead are adaptations to different circumstances“ (p. 1101).