Early Career Outstanding Paper Award winner: Marije Verhage

Continuities across generations have intrigued researchers in multiple domains of human functioning, including the attachment relationship between caregivers and children. Decades of research inspired by the attachment theory (Bowlby, 1969/1982) has provided many insights into the emergence of the attachment relationship, among which the finding that mental representations that caregivers have built up based on their own attachment experiences with their parents predict the quality of the attachment relationship with their own children (Main, Kaplan, & Cassidy, 1985). This intergenerational transmission of attachment has been studied extensively over the past three decades.

Our article (Verhage et al., 2016), which was recently published in Psychological Bulletin , aimed to thoroughly evaluate the status of the intergenerational transmission of attachment by synthesizing these 30 years of research in a series of meta-analyses. Research questions were aimed at examining the robustness of intergenerational transmission of attachment and at testing the generalizability of the effect across normative and clinical populations, methodological variation and time. Also, the mediating role of caregiver sensitivity was scrutinized carefully, which only partly explained the transmission of attachment in a meta-analysis of the first wave of studies on attachment transmission (van IJzendoorn, 1995).

The search for eligible studies was a large undertaking, as it included a massive hunt for unpublished studies. In the end, 97 samples were identified, over half of which were previously unpublished. The results of the study supplemented attachment theory in several ways. First, a robust effect for attachment transmission was found, confirming it as a universal phenomenon. However, the study also showed that attachment transmission was not equally strong in all scenarios: The effect size varied by characteristics of the caregiver-child dyads. For example, transmission rates were lower in samples with an at-risk background, such as teenage parents and parents with psychopathology. Also, a gradual decline in effect size over the years was discovered, which could not be explained by the fact that more studies were performed in at-risk populations in later years. Attachment transmission was also lower for unpublished studies, which suggests a publication bias towards significant results. Finally, the mediating effect of caregiver sensitivity was equally limited in the current study as it was 20 years ago, which underlines the need for alternative explanations of attachment transmission.

The Implications

This study has substantial implications for attachment theory and research. We systematically integrated the novel findings of the study into the existing theoretical model, building towards an augmented theoretical model of intergenerational transmission of attachment that opens up new avenues for research, particularly research into the conditions that determine whether transmission occurs or not. Furthermore, as the effect size of attachment transmission has decreased, this leaves room to generate ideas on new predictors of caregiver-child attachment besides caregiver attachment representations. In a broader sense, the findings of this meta-analysis underscore the importance of considering decreases in effect size and publication bias for evaluating the status of theories in psychological science.

The Future

By synthesizing 30 years of research on attachment transmission, we took the first steps towards more definite answers to long-standing questions in the field of attachment. However, many fine-grained questions on the mechanisms behind attachment transmission remain yet to be answered, and we feel that the key to answering these questions lies in collaborative science. Due to the labor-intensive methods used to measure attachment, large samples are rare in this field. However, to examine these fine-grained questions and extensive theoretical models, large samples are a necessity. Therefore, we came up with the idea of pooling the existing data of all researchers to perform individual participant data meta-analysis (Riley, Lambert, & Abo-Zaid, 2010), which is a more fine-grained technique for meta-analysis that allows us to study the data at the level of the individual participant. With this idea of collaborative science in mind, we initiated an international consortium of researchers who studied attachment transmission to try to combine their existing study data into a large database. The responses to this endeavor were positive, and the consortium currently consists of over 60 researchers who work together to take the next steps in attachment transmission research. The enthusiasm and commitment of these study authors in the consortium is evident not only from the high response rate but also from their participation in the collaborators meeting we had last summer.

As we are currently still in the process of data collection and preliminary analyses, it is still possible to join the consortium. Together with the traditional meta-analysis that was awarded the Early Career Outstanding Paper award, this project has the potential to broadly impact the field of developmental psychology.

References

Bowlby, J. (1969/1982). Attachment and loss: Vol. 1. Attachment. New York: Basic Books.

Main, M., Kaplan, N., & Cassidy, J. (1985). Security in infancy, childhood, and adulthood: A move to the level of representation. In I. Bretherton & E. Waters (Eds.), Growing points of attachment theory and research. Monographs of the Society for Research in Child Development, 50 (1-2, Serial No. 209), 66-104. doi: 10.2307/3333827

Riley, R. D., Lambert, P. C., & Abo-Zaid, G. (2010). Meta-analysis of individual participant data: Rationale, conduct, and reporting. British Medical Journal, 340, c221. doi: 10.1136/bmj.c221

van IJzendoorn, M. H. (1995). Adult attachment representations, parental responsiveness, and infant attachment: A meta-analysis on the predictive validity of the Adult Attachment Interview. Psychological Bulletin, 117 (3), 387-403.

Verhage, M. L., Schuengel, C., Madigan, S., Fearon, R. M. P., Oosterman, M., Cassibba, R., et al. (2016). Narrowing the transmission gap: A synthesis of three decades of research on intergenerational transmission of attachment. Psychological Bulletin, 142 (4), 337-366. doi: 10.1037/bul0000038