A Functional Neuro-Anatomical Model of Human Attachment (NAMA)

In 2012, Patrik Vuilleumier and I have published a first review paper on the social neuroscience of human attachment in Frontiers in Human Neuroscience (see here). This review paper included a functional neuro-anatomical model of human attachment (more recently termed NAMA – part of an upcoming extended and refined review paper that has just been accepted in the journal Cortex; will be updated here soon). The most recent version of NAMA that is currently available is part of a book chapter on “The Social Neuroscience of Attachment“ published in 2017. Below is a Figure depicting the 2017 version of NAMA:

Fig_1
Functional neuro-anatomical model of human attachment (NAMA; Vrticka , 2017)

Description of NAMA

In the above functional neuro-anatomical model of human attachment (NAMA), Patrik Vuilleumier and I differentiate between an affective evaluation and a cognitive control system. While the affective evaluation system is thought to process incoming information rather quickly and automatically (i.e. bottom-up), the cognitive control system likely represents more voluntary regulatory processes that can modulate affective evaluation mechanisms (i.e. top-down). We further differentiate the affective evaluation system into an approach and an aversion module, and the cognitive control system into an emotion regulation and a mental state representation module.

The so far available data (mainly from adults) suggest that the organized attachment orientations / classifications of insecure-avoidant and insecure-anxious (as compared to secure) differentially influence affective evaluation and cognitive control mechanisms. While both insecure attachment orientations appear to (at least partially) interfere with emotion regulation mechanisms as part of the cognitive control system (see also here), attachment avoidance and anxiety seem to have opposite effects on affective evaluation processes. Attachment avoidance may be mainly associated with a general blunting of affective evaluation processes, particularly in the case of positive social information (neurally represented in the approach module). In turn, attachment anxiety may be mainly linked to a general intensification of affective evaluation processes, especially in the case of negative social information (neurally represented in the aversion module).

As mentioned above, we recently further refined and extended our functional neuro-anatomical model of human attachment (NAMA) by integrating more of the recent literature and embedding it into a prototypical attachment pathway that adds explanation to the function and implication of the four involved modules. The corresponding article has just been accepted for publication in the journal Cortex and will become available very soon.

In addition, we just submitted a first attempt to extend NAMA to attachment disorganization and trauma (“A Functional Neuro-Anatomical Model of Disorganized Attachment – NAMDA“).

More information on NAMA and NAMDA will be made available here as soon as possible.

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, 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 problems if the associated secondary attachment strategies are employed chronically and out of context, and/or if there is a complete lack of strategies altogether.

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. More cross-cultural research therefore is still crucially needed to further extend and specify attachment theory and the emerging applied attachment research – including the above 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).

Different Neurobiological Accounts of Human Attachment

Finally, it should be mentioned here that there are other neurobiological accounts of human attachment available in the literature. A nice summary can be found in a book chapter by Gillath, Karantzas, & Fraley (2016): “What Can Neuroscience, Genetics, and Physiology Tell Us About Attachment?“.

In our view, one prominent account by Helen Fisher (see, for example, here) suggests that three principal human social behaviors can be dissociated by their underlying neurotransmitter / -peptide systems: (1) the sex drive / lust mediated by androgens, (2) attraction / mate choice / romantic love mediated by catecholamines, and (3) attachment (understood as a long-term non-sexual bond between individuals; child-parent, but also romantic partners, etc.) mediated by oxytocin.

A second prominent account by Ruth Feldman (for a recent review, see here) suggests a differentiation of human attachment behaviors by means of four principal mammalian bonds, namely: (1) parent-infant bonds, (2) pair-bonds, (3) peer bonds, and (4) bonds between conspecifics. Furthermore, Ruth Feldman proposes that the strenght of these bonds can be categorically distinguished by their degree of bio-behavioral synchrony expressed within the bond – with parent-infant bonds having the strongest degree of bio-behavioral synchrony.

In our above-described functional neuro-anatomical model of human attachment (NAMA) we propose, the models by Fisher and Feldman are also considered. These models, however, are extended by the notion put forward by attachment theory that the very same mammalian bond / attachment  – mediated by the very same neurotransmitter / -peptide systems – can be subjected to strong inter-individual differences depending on the quality of the bond and thus attachment. For example, parent-infant bonds may be generally characterized by high bio-behavioral synchrony and prominently mediated by oxytocin, but strong inter-individual differences in the bio-behavioral signature are to be expected depending on the quality of the bond – the latter being reflected in secure versus insecure, anxious and/or avoidant attachment orientations / classifications (not only on the individual but also the dyadic and family level). Inter-individual differences therefore are key in NAMA and we are particularly interested in describing their influence on the psychological, behavioral, biological, physiological, and neural basis of human attachment.