Running Head: Representing Attachment 1

Home , Mary Ainsworth

Running head: Representing Attachment 1

Representing attachment through meta-analyses: A move to the level of collaboration

Carlo Schuengel1, Marije L. Verhage

Vrije Universiteit Amsterdam

Robbie Duschinsky

University of Cambridge

Author Note

Clinical Child and Family Studies, Faculty of Behavioural and Movement Sciences and

Amsterdam Public Health research institute, Vrije Universiteit Amsterdam, The Netherlands

Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands, [email protected] Representing Attachment 2

Word count: 2,473

Number of references: 24 Representing Attachment 3

ABSTRACT

Generations of researchers have tested and used attachment theory to understand children’s development. To bring coherence in the expansive set of findings, the field early on adopted meta-analysis, with 75 published since 1987. These meta-analyses are increasingly applied in research on disorder and intervention, and in self-report research on attachment anxiety and avoidance in adolescents. However, conventional approaches to meta-analysis have left thorny issues unresolved regarding the intergenerational transmission of individual differences in attachment. We discuss how attachment research has been addressing these challenges by collaborating to pooling data and resources in individual participant data meta- analyses, leading to novel insights and greater theoretical precision.

Keywords: attachment, intergenerational effects, meta-analysis, bibliometrics, individual participant data Representing Attachment 4

Representing Attachment: A Move to the Level of Collaboration

Attachment is seen in children’s protest and proximity-seeking behavior if they are involuntarily separated from their familiar caregiver. It is also seen in children’s confident exploration of novelty when children perceive that their caregiver is there to protect them from harm (Tottenham, Shapiro, Flannery, Caldera, & Sullivan, in press). Children develop secure attachment relationships with caregivers who are sensitively responsive to the signals and needs of their child, and may develop insecure attachment relationships with caregivers who ignore these needs or respond only intermittently, which contribute to diverging developmental pathways of social functioning and mental health (Ainsworth & Bowlby, 1991). Research on attachment has examined determinants and outcomes of attachment across a broad range of biopsychosocial factors. To summarize the empirical evidence for such links, the field of research on child attachment was an early adopter of meta-analysis. Meta-analysis was called upon to address debates in attachment theory regarding the role of child temperament as an explanation for individual differences (Goldsmith & Alansky, 1987) and the relative species- wide universality of child attachment patterns (Van IJzendoorn & Kroonenberg, 1988). Van

IJzendoorn was an especially influential disseminator of the methodology, influenced by Karl

Popper’s emphasis on the need for replication as the basis of surety in science (Van IJzendoorn,

1994). Both to provide such surety, and to examine explanations for different outcomes among Representing Attachment 5

studies, meta-analysis became an important instrument to represent empirical evidence and to inform the future direction of attachment research.

In 1985, Main, Kaplan, and Cassidy proposed that caregivers’ own state of mind regarding attachment, classified as autonomous (secure), dismissing, preoccupied, or unresolved on the basis of the Adult Attachment Interview, determines the security of children’s attachment relationships by influencing the sensitivity of caregivers’ responses to children. The importance of intergenerational transmission for developmental and clinical psychology lies both in what it can tell us about the contribution of caregivers to their children’s social functioning and mental health, and in what it can tell us about factors that interrupt this contribution. In 1995, Van

IJzendoorn published a meta-analytical effect size based on 18 studies of a strength seldom seen in psychological science (r = 0.47/d = 1.06; N = 854), which helped to win acceptance among the research community for Main et al.’s Adult Attachment Interview as a predictor of individual differences in infant-caregiver attachment. However, Van IJzendoorn’s meta-analysis also showed that Main et al.’s model could not fully account for how transmission and non- transmission came about. This finding became known as the ‘transmission gap’ and led to numerous theoretical and empirical efforts to close it (Van IJzendoorn & Bakermans-

Kranenburg, 2019). Yet over the years a string of studies, including fairly large ones, also reported null findings for intergenerational transmission. This casted doubt on the replicability of intergenerational transmission, prompting a new meta-analysis. With over four times as much Representing Attachment 6

data as available from 83 samples, Verhage et al. (2016) reported a considerably lower but still relatively strong (Funder & Ozer, in press) effect size (r = .31/d = 0.65; N = 4,102). Studies showed significant heterogeneity in these outcomes, however, which could not be more fully explained without access to finer-grained individual participant data.

This paper begins by appraising the scope and impact of meta-analysis on child attachment, which have been important focal points of the field. In the second part of the paper we discuss how individual participant data meta-analysis (Riley, Lambert, & Abo-Zaid, 2010) offers a collaborative model to overcome the limitations of traditional meta-analyses and single studies to further understand intergenerational transmission.

META-ANALYSES OF CHILD ATTACHMENT RESEARCH

A bibliometric study retrieved all published (up to June 9, 2019) meta-analyses that synthesized descriptives or effect sizes based on attachment assessment with children (up to age

18) and their caregivers across the field of psychology. Full details of the work using Vosviewer

(Van Eck & Waltman, 2016) and Bibliometrix (Aria & Cuccurullo, 2017) software can be found in Schuengel, Verhage, and Duschinsky (2019). To date, 75 meta-analyses have been published.

Publication rate shows exponential growth up to and including 2018. Also the number of different authors of meta-analyses (often in co-authorship with Van IJzendoorn and Bakermans-

Kranenburg) has steadily increased. Representing Attachment 7

Among the meta-analyses are those with aims to test or further specify attachment theory

(e.g., testing propositions about the link between parenting and attachment, or between attachment and developmental outcomes), psychometric aims (e.g., reliability and validity of attachment instruments), epidemiological aims (e.g.,describing prevalences across populations), and aims related to understanding intervention (e.g., efficacy of attachment-based interventions).

Figure 1 shows cumulative trends over time (1987-2018) in these aims. While the first period reveals an exclusive focus on testing and elaborating attachment theory, from 2004 largely stable proportions can be seen of published meta-analyses with theoretical aims (53%), psychometric aims (8%), epidemiological aims (24%), and aims related to intervention (15%). Representing Attachment 8

Figure 1. Cumulative count of attachment meta-analyses according to main study aim.

Reception of Meta-Analyses

As of June 9, 2019, the meta-analyses on attachment had been cited in 7,595 publications, growing at an annual rate of 24% per year up to and including 2018. To put this into perspective, the landmark publication by Ainsworth et al. (1978) that initiated empirical attachment research was cited in total 8,641 times, peaking at 480 citations in 2015.

Clusters based on machine reading for meaningful terms and phrases in titles and abstracts are shown in Figure 2, based on a cut-off of terms being used in at least 100 papers. Representing Attachment 9

Figure 3 shows the same clusters, with colour gradient indicating average year of the publications from which these terms were drawn. For each of the clusters we provide a brief interpretation.

Figure 2. Network clusters of nouns and adjective-noun combinations extracted by natural language processing of titles and abstracts of publications that cited attachment meta- analyses. Representing Attachment 10

Figure 3. Network of nouns and adjective-noun combinations extracted by natural language processing of titles and abstracts by average year of publication citing attachment meta- analyses.

The red cluster depicts a network of 34 terms referring to intervention. Besides

‘intervention’, dominant terms include ‘treatment’, ‘program’, ‘practice’, ‘need’, ‘process’, and

‘abuse’. The overlay of publication year of the articles from which these terms were derived indicates increasing interest in this set of topics. Representing Attachment 11

The green cluster depicts a network of 33 terms that reflect the vocabulary that

Ainsworth, the founder of attachment research as an empirical paradigm, proposed for describing parent-child relationships. Besides ‘mother’, ‘infant’, and ‘father’, dominant terms are

(attachment) ‘security’, ‘responsiveness’, and (maternal) ‘sensitivity’. The overlay of publication year shows, overall, a decrease of attention to the topics in this cluster relative to the other clusters. However, research on sensitivity and on fathers specifically has been increasing among papers citing the meta-analyses, following an opposed trend.

The blue cluster depicts a network of 29 items that refer to attachment styles as conceptualized within the social psychological tradition of self-report assessments of attachment

(Roisman, 2009). Dominant terms in addition to ‘attachment style’ are ‘questionnaire’,

‘attachment theory’, ‘adolescent’/’adolescence’, ‘adult’, and ‘anxiety’. While the terms attachment style and attachment theory appear to be used less over time in the field demarcated by attachment meta-analyses, attention has increased in attachment anxiety and avoidance. This follows the identification of these as the latent dimensions of individual differences in adult attachment by Brennan et al. (1998), which helped to retire the category-focused concept of

‘attachment style’ previously used by the social psychological tradition. Attachment anxiety and avoidance have, since then, become synonymous with attachment theory for social psychologists

(e.g., Mikulincer & Shaver, 2003), likely contributing to the decline of the latter term. Representing Attachment 12

The yellow cluster consists of a smaller network of 14 items referring to disorder. The cluster is dominated, in addition to the term ‘disorder’, by terms around ‘symptom’, ‘depression’, and ‘psychopathology’. With this cluster straddling the intervention-cluster, the publication years of the underling articles indicate a similar increase in attention in this field.

The purple cluster contains 10 items, identifying interest in attachment representations, also denoted as state of mind regarding attachment (Main et al., 1985). Terms that form this cluster are ‘Adult Attachment Interview’, ‘AAI’, ‘state’ (of) ‘mind’, and (attachment)

‘representation’. The publication years underlying this set of terms suggest that interest in these aspects is decreasing relative to the other topics in this field.

A Move to the Level of Intervention… and Self-Report

The science map shows that while a relative majority of meta-analyses are still concerned with theoretical issues, the number of meta-analyses on interventions as well as the number of publications about clinical issues and interventions that refer to meta-analytic evidence on attachment is rapidly increasing. Furthermore, the proportion of publications that refer to mothers and children using the classic terminology introduced by Mary Ainsworth and to attachment state of mind as conceptualized by Mary Main has been relatively decreasing among studies citing attachment meta-analyses. At the same time there appears to have been an increasing impact of attachment meta-analyses on research using self-report instruments for attachment anxiety and avoidance in adolescence and adulthood. While these trends may reflect Representing Attachment 13

genuine shifts in interest, research strategies may also play a role. Social psychology more broadly has seen an increase in self-report and online data collection, which is explained by increasing awareness of the need to have sufficient statistical power (Sassenberg & Ditrich,

2019). Attachment research in the developmental tradition uses observational and interview instruments that are particularly taxing for research participants and time-consuming and difficult to master for researchers (Duschinsky, 2020). This raises the question whether there are alternative ways to address issues of statistical power, participant burden, and measurement reliability.

REVISITING INTERGENERATIONAL TRANSMISSION

A meta-analysis by Verhage et al. (2016) highlighted the need to better understand the factors that moderate the strength of transmission, showing that studies with weak transmission were less often published, which may have led to less attention to the issue of moderation than needed on the basis of data. Effect size estimates were weaker if families had higher numbers of psychosocial risk factors. A novel finding, consistent with the mechanisms of attachment transmission, suggested that attachment transmission was higher in strength when children were older, having received more interactive experience with their parents. However, there were insufficient studies that tested more complex models to settle this issue with traditional meta- analysis, and new primary studies would require prohibitively large sample sizes. Representing Attachment 14

A Move to the Level of Collaboration

Individual participant data (IPD) meta-analysis is increasingly adopted within the medical sciences to overcome the limitations of meta-analyses based on aggregate data (Riley et al.,

2010). The developmental approach to attachment research provides fertile ground for this approach. First, the field is characterized by unusually consistent use of the same assessment paradigms for attachment constructs, such as the Strange Situation Procedure (Ainsworth et al.,

1978) and the Adult Attachment Interview (Main et al., 1985). This considerably reduces the problem of harmonizing the operationalization of key variables across studies and increases the scope for testing complex multivariate models. Second, the time-intensive nature of data collection and coding raises the threshold for destroying data, leading to high data availability, even of data from decades ago.

Setting up the collaboration, identifying datasets, inviting principal investigators, collating and harmonizing the data, and developing novel algorithms for one-stage IPD meta- analysis of categorical data made possible the first publication by the Collaboration of

Attachment Transmission Synthesis (CATS) group (Verhage et al., 2018). The paper included data on parents’ Adult Attachment Interview classification and children’s Strange Situation classification or Attachment Q-Sort score from 4,396 parent-child dyads originating from 58 independent studies. It showed that attachment transmission grew stronger as children became older. While this was also reported in the traditional meta-analysis (Verhage et al., 2016), the

IPD results were much more robust and controlled for confounding due to parental age and type Representing Attachment 15

of attachment measure. This finding shows how small effects of attachment representations on caregiver-child attachment may become more consequential when allowed to accumulate and underscores the importance of preventive early intervention, even if child attachment is not yet insecure. The IPD meta-analysis also pinpointed how family risk specifically lowers the likelihood of secure child attachment if parents have autonomous attachment representations, while risk status does not exacerbate the risk of insecure attachment among children of parents with nonautonomous representations. This novel finding suggests that autonomous parental representations are unlikely to offer resilience against contextual risk, underscoring the need to better understand the impact of family risk factors on attachment relationships.

Further investigations of a subset of 2,287 dyads from 32 samples with observational data on sensitive parenting (Verhage et al., 2019) showed that parental sensitivity accounts for 16% of the intergenerational transmission effect. It furthermore revealed that risk specifically weakens the link between caregiver sensitivity and attachment, and not the link between states of mind regarding attachment and sensitivity. This finding will help to better focus future research into the transmission gap.

CONCLUSIONS

Wide-scale collaboration among attachment researchers in IPD meta-analysis has brought rigorous testing of complex attachment theoretical propositions into reach, while also enabling the exploration of the boundaries of these propositions. First efforts are underway to Representing Attachment 16

also employ IPD meta-analysis for answering psychometric questions, such as the latent structure of attachment representations (Raby et al., 2019). New IPD meta-analyses are also underway to better understand the mechanisms and moderators of attachment-based interventions, as well as the impact of children’s multiple attachment relationships. By sharing data, resources (such as the secure IT infrastructure built for this purpose), scripts, and protocols

(see https://osf.io/kc9z2/) the field may address theoretical challenges, increase its methodological rigor and transparency, and strengthen its capacity to inform applied research.

The collaborative model means that sharing hard-won and valuable attachment data goes hand in hand with directly and intensively interacting with a large community of attachment researchers in the initiation phase of research, deliberating and critically reviewing a priori new hypothesis, and gaining access to a large, carefully curated pool of data for testing these. Together with other efforts to make psychological science more robust (Nelson, Simmons, & Simonsohn, 2018), IPD meta-analyses show both the value and the viability of moving to new levels of collaboration in attachment research. Representing Attachment 17

NOTES

1Address correspondence to Carlo Schuengel, Vrije Universiteit Amsterdam, Van der

Boechorststraat 7, 1081 BT Amsterdam, The Netherlands. E-mail: [email protected] Representing Attachment 18

REFERENCES

Ainsworth, M. D. S., Blehar, M. C., Waters, E., & Wall, S. (1978). Patterns of attachment.

Hillsdale, NJ: Lawrence Erlbaum.

Ainsworth, M. D. S., & Bowlby, J. (1991). An ethological approach to personality development.

American Psychologist, 46, 333-341.

Aria, M. (2017). bibliometrix: An R-tool for comprehensive science mapping analysis. Journal

of Informetrics, 11(4), 959–975. doi:10.1016/j.joi.2017.08.007

Brennan, K. A., Clark, C. L., & Shaver, P. R. (1998). Self-report measurement of adult

attachment: An integrative overview. In J. A. Simpson & W. S. Rholes (Eds.),

Attachment theory and close relationships (pp. 46-76). New York: Guilford.

Duschinsky, R. (2020). The cornerstones of attachment research. Oxford: Oxford University

Press

Funder, D. C., & Ozer, D. J. (in press). Evaluating effect size in psychological research: Sense

and nonsense. Advances in Methods and Practices in Psychological Science.

doi:10.1177/2515245919847202

Goldsmith, H.H., & Alansky, J.A. (1987). Maternal and infant temperamental predictors of

attachment: A meta-analytic review. Journal of Consulting and Clinical Psychology,

55(6), 805-816. Representing Attachment 19

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 (Vol. 50 (1-2), pp. 66-104): Society for Research in

Child Development.

Mikulincer, M., & Shaver, P.R. (2003). The attachment behavioral system in adulthood:

Activation, psychodynamics, and interpersonal processes. In M.P. Zanna (Ed.), Advances

in Experimental Social Psychology (Vol. 35, pp.53-152). New York: Academic Press

Nelson, L. D., Simmons, J., & Simonsohn, U. (2018). Psychology's Renaissance. Annual Review

of Psychology, 69(1), 511-534. doi:10.1146/annurev-psych-122216-011836

Raby, K. L., Verhage, M. L., Fearon, R. M. P., Fraley, R. C., Roisman, G. I., Van IJzendoorn, M.

H., ... Collaboration on Attachment Transmission Synthesis (2019). The latent structure

of the Adult Attachment Interview: Large sample evidence from consortium data. Paper

presented at Biennial Meeting of the Society for Research in Child Development, MD

Riley, R. D., Lambert, P. C., & Abo-Zaid, G. (2010). Meta-analysis of individual participant

data: rationale, conduct, and reporting. British Medical Journal, 340.

doi:10.1136/bmj.c221

Roisman, G. I. (2009). Adult attachment: Toward a rapprochement of methodological cultures.

Current Directions in Psychological Science, 18(2), 122-126.

Sassenberg, K., & Ditrich, L. (2019). Research in social psychology changed between 2011 and

2016: Larger sample sizes, more self-report measures, and more online studies. Advances Representing Attachment 20

in Methods and Practices in Psychological Science, 2(2), 107-114.

doi:10.1177/2515245919838781

Schuengel, C., Verhage, M.L., & Duschinsky, R. (2019, July 14). Representing attachment:

Bibliometric study. Retrieved from osf.io/hxez2

Tottenham, N., Shapiro, M., Flannery, J., Caldera, C., & Sullivan, R. M. (in press). Parental

presence switches avoidance to attraction learning in children. Nature Human Behaviour.

doi:10.1038/s41562-019-0656-9

Van Eck, N. J., & Waltman, L. (2016). VosViewer (Version 1.6.10). Software retrieved from

http://www.vosviewer.com/

Van IJzendoorn, M. H. (1994). Process model of replication studies: on the relations between

different types of replication. In R. Van der Veer, M. H. Van IJzendoorn, & J. Valsiner

(Eds.), On reconstructing the mind: Replicability in research on human development (pp.

57-70). Norwood, NJ: Ablex.

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.

Van IJzendoorn, M. H., & Bakermans-Kranenburg, M. J. (2019). Bridges across the

intergenerational transmission of attachment gap. Current Opinion in Psychology, 25, 31-

36. doi:10.1016/j.copsyc.2018.02.014 Representing Attachment 21

Van IJzendoorn, M. H., & Kroonenberg, P. M. (1988). Cross-cultural patterns of attachment: A

meta-analysis of the strange situation. Child Development, 59, 147-156.

Verhage, M. L., Fearon, R. M. P., Schuengel, C., Van IJzendoorn, M. H., Bakermans-

Kranenburg, M. J., Madigan, S., . . . Collaboration for Attachment Transmission

Synthesis (2018). Examining ecological constraints on the intergenerational transmission

of attachment via individual participant data meta-analysis. Child Development, 89(6),

2023-2037. doi:10.1111/cdev.13085

Verhage, M. L., Fearon, R. M. P., Schuengel, C., Van IJzendoorn, M. H., Bakermans-

Kranenburg, M. J., Madigan, S., ... Collaboration on Attachment Transmission Synthesis

(2019). Does risk background affect intergenerational transmission of attachment?

Testing a moderated mediation model with IPD. Paper presented at Biennial Meeting of

the Society for Research in Child Development, MD.

Verhage, M. L., Schuengel, C., Madigan, S., Fearon, R. M. P., Oosterman, M., Cassibba, R., . . .

Van IJzendoorn, M. H. (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 Representing Attachment 22