Did Insecure Attachment Styles Evolve for the Benefit of the Group?

of insecure attachment styles, according to Ein-Dor et al., is that across evolutionary time, the costs of insecure attachment styles to individuals were exceeded by benefits at the group-level. These group-level benefits are considered a driving selective force, not accidental byproducts of strategies that are individually advantageous – hence the paradox. The central idea is that insecure attachment styles are suboptimal to the individual, yet prevalent: this “evolutionary paradox” is resolved by positing group-level benefits. On this view, insecurely attached individuals are evolutionary altruists: they incur a fitness cost to enhance the fitness of other individuals in the group. Here, I first question the existence of the “attachment paradox” and then the solution proposed by Ein-Dor et al. (2010). For attachment research to benefit from evolutionary biology, it is important that ideas about evolutionary processes, as well as assumptions about our human evolutionary history, are correct and, whenever possible, complete. Thus, an integration of evolutionary and developmental science requires, in addition to empirical studies, conceptual analyses and discussion of key premises. The hypothesis of Ein-Dor et al. (2010) assumes that insecure attachment styles are maladaptive to the individual: however, the authors do not provide sources to support this claim. To my knowledge, the fitness effects of attachment strategies have never been measured in humans. It would be most informative if studies compared the number of viable offspring (or a different proxy for fitness) of individuals with insecure versus other attachment styles, in conditions in which insecure attachment styles tend to develop. Ideally, such studies would be conducted cross-culturally, in order to ensure results generalize across socio-ecological conditions, or to document and understand variation (Henrich Did insecure attachment styles evolve for the benefit of the group?