The insecurely attached brain: How early social interactions can shape adult brain function

This blog post first appeared on http://thepeoplesscience.org/ on October 29, 2016, and has since been edited to reflect advances in attachment theory and research (see also here and here for more information).

In a first review paper within the field, Patrik Vuilleumier and I recently proposed a model describing how attachment insecurities associate with social brain function in healthy adults (this model has more recently been named functional neuro-anatomical model of human attachment, or NAMA). It has been known for more than four decades that early social interactions can crucially shape social behavior throughout the lifespan. Evidence regarding the underlying neural mechanisms, however, has only started to emerge during the last years. Because attachment insecurities have a high prevalence, can be transmitted across generations, and increase the risk for social and emotional problems, we hope that our model can help advancing new prevention and treatment approaches.

Humans are a highly social species. We enjoy the company of friends and like sharing our personal experiences with others. Mutual social interactions and self-disclosure usually entail increased activity in our brain’s reward circuit: the very same network that is activated by basic reinforcers such as food or sex. It simply feels good to be social. Conversely, when we are socially excluded, activity increases in areas of our brain that respond to salient information and also mediate physical pain responses. Social rejection grabs our attention and really does hurt.

In some people, however, these intrinsic links between social approach versus aversion behavior and brain activity appear to be wired somewhat differently. Furthermore, such different neural wiring seems to trace back to varying experiences of social interactions in early life. The brains of avoidantly attached healthy adults have been found to less strongly activate, but the brains of anxiously attached adults to more readily respond to social clues. Yet, what does it mean to be avoidantly or anxiously attached?

Attachment theory proposes that (almost) every child is born with an innate attachment system. Its biological function is to enhance survival through proximity seeking in times of need. Although (almost) all children become attached to a caregiver to survive, the quality of their attachment can vary. In the case of emerging attachment avoidance, children likely experience repeated interactions with unresponsive and/or unavailable attachment figures. They therefore learn to expect and predict social rejection and have fewer opportunities to associate social interactions with positive  feelings and reward. In the case of emerging attachment anxiety, children likely experience repeated interactions with inconsistent attachment figures. Sometimes children are comforted by others, sometimes rejected, and this in an unpredictable way. As a consequence, anxiously attached children become increasingly sensitive to cues of social approval and disapproval.

Attachment theory furthermore states that early social interaction patterns remain rather stable during the lifespan (but they can, and do, change: see here). An insecure attachment style can thus influence social behavior and associated brain anatomy and function from childhood through adolescence and adulthood. In addition, evidence summarized in our review paper indicates that attachment insecurities not only affect directly attachment-related processes (e.g., parent-infant relationships), but (almost) all social interactions, even with strangers.

Roughly 40% of individuals are insecurely attached. In addition, the plot thickens that attachment insecurities can be transmitted across generations. Insecurely attached people also run a higher risk for developing physical and mental health problems. A better understanding of the neural basis of insecure attachment therefore is of high general interest. If we learn how to help children feel more secure in their attachment, we can proactively increase the wellbeing of future generations.

The above described review paper appeared in Frontiers of Human Neuroscience in 2012, and is freely available here:
http://www.frontiersin.org/Human_Neuroscience/10.3389/fnhum.2012.00212/full.

A more recent review and updated model (NAMA) appeared in Cortex in 2020, and is freely available here: https://doi.org/10.1016/j.cortex.2020.01.010.

Finally, an extension of NAMA to disrupted / disorganised attachment (NAMDA) appeared in Frontiers in Psychiatry in 2020, and is freely available here:
https://doi.org/10.3389/fpsyt.2020.517372.