Mentalizing Adolescence: Reflective Functioning Capacities in Parents of Identical Twins and its Relationship to Adolescent Attachment

  • Research Project Team

    Pia Tohme

    Supervisors: Yael Shmueli Goetz, Mary Target, Pasco Fearon and the TEDS project


  • Background

    Fonagy et al. (1997) defined maternal Reflective Functioning (RF) as the mother’s ability to attribute feelings, thoughts and desires underlying her own and her baby’s behaviours as well as to hold her baby and his mental states in her mind in a non-defensive way in order to allow him to discover his internal world through her representation of it (Fonagy et al., 1991; Fonagy, 2008; Slade, 2005).

    Parental RF was consistently found to be the best predictor of attachment in infancy (Fonagy et al., 1991; Fonagy & Target, 1997; Slade et al., 2005). However, can it be argued that this relationship remains in adolescence? Most of the research on parental mentalization has focused on parents of infants and young children, with very few looking at parental mentalization of middle childhood and only one investigated parental RF in adolescence (Arnott & Meins, 2007; Meins et al., 2001; Benbassat & Priel, 2011; Slade et al., 2005, de Wolff & van Ijzendoorn, 1997).

    However, it can be hypothesized that parental RF could facilitate the adolescents’ experiences during this period, as well as lead to a better understanding of feelings and thoughts underlying their behaviours (Benbassat & Priel, 2011). Looking at the association between maternal sensitivity and attachment in the specific case of twins, two studies have been conducted resulting in somewhat contradicting results. Both found that the relationship between infant attachment and parental sensitivity was mostly accounted for by shared environmental factors given that in cases of concordant attachment between the twins, maternal sensitivity was positively associated with infant security (Fearon et al., 2006; Roisman & Fraley, 2008).

    However, in cases of discordant attachment between the infants, Fearon et al. (2006) found that maternal sensitivity was found to be negatively correlated to attachment security, meaning that mothers’ sensitivity to one twin but not the other led to insecurity in the twin receiving higher levels of sensitivity whereas Roisman and Fraley (2008) found that maternal sensitivity was higher towards the securely attached child.

  • Aims

    • The first aim of this research was to investigate, on an inter-familial level, whether there is a shared influence on adolescent attachment from the overall level of both, maternal and paternal RF.
    • The second aim of this study was to explore whether additional shared family factors or adolescent characteristics, such as adolescent gender, family income, parental education and the number of siblings in the family (Cutting & Dunn, 1999; Fearon et al., 2006) have a direct influence on parental RF
    • The third aim of this study was to investigate whether differences in a parent’s RF about each twin, examining parental RF of mothers and fathers separately, constitute a non-shared environmental influence on adolescent attachment. Additionally, differences in the quality of the twins’ relationships to peers and differences in the quality of the twins’ relationship to each other were examined as potential factors, linked to adolescent attachment.
    • The fourth aim of this study was to examine, through a case study, additional child-specific factors that could be associated with attachment discordance between identical twins.
  • Methodology


    1000 families were recruited for a project run at the Anna Freud Centre (AFC) and Institute of Psychiatry (IoP) aiming to look at the behavioural genetics of attachment in adolescence, using the Child Attachment Interview (CAI; Shmueli-Goetz et al., 2008; Target, Fonagy & Shmueli-Goetz, 2003).

    For the purpose of the current study interviewing parents, the author selected 100 families of identical twin pairs (MZ) who had completed the CAI through the study at the AFC/IoP within the past 10 months.


    A short version of the Parent Development Interview (PDI; Aber, Slade, Berger, Bresgi, and Kaplan, 1985) coded on RF as a measure of parental reflective functioning -the coherence scale of the Child Attachment Interview (Shmueli-Goetz, Target, Fonagy & Datta, 2008) as a measure of adolescent attachment Procedure: -Adolescents were interviewed first as part of a joint study run by the AFC/IoP. The average interview lasted between 30 and 45 minutes. -Parents were later contacted for the interviews, between 2 and 10 months after the twins’ interviews were completed. The PDI was conducted twice, once about each twin, simultaneously for mother and father, in separate rooms. The author interviewed one parent about both twins while the other researcher interviewed the second parent, following the same procedure. Questions were first asked about the first born twin. On average, visits lasted an hour in total.

  • Results

    The current twin study represents a unique study and the first of its kind to examine the relationship between maternal and paternal mentalization and adolescent attachment. The association between parental reflective functioning and adolescent attachment provided some support for predictions of attachment theory. Shared environmental effects of parental reflective functioning were found to correlate significantly with the shared variance in adolescent attachment coherence. Thus, the similarity between twins’ coherence scores was partially explained by consistencies in their experience of parental reflective functioning. However, an influence of shared genes on adolescent coherence was also suggested given the moderate correlation found between twins’ coherence scores. Examining maternal and paternal RF separately, strong associations were found between mothers’ and fathers’ RF scores, which were found to, partially independently, influence twins’ coherence at the family level only. This suggests similarities between maternal and paternal RF scores but also highlights the importance of both mothers’ and fathers’ mentalizing capacities in determining their twins’ attachment coherence. The current study failed to identify non-shared environmental influences of parental RF on adolescent coherence and the need for a full behavioural genetics study including MZ and DZ twins was suggested. Finally, based on a case study analysis, it was suggested that the interaction between a number of non-shared factors, such as twins’ level of psychological maturity, their potential de-identification from each other and from their parents, their perception of the twinship relationship and the parents’ description of each twin, could explain discrepancies between twins’ attachment classification. Research into the specific causes and effects of non-shared environmental influences on development is still in its infancy, and further work is clearly needed to identify other factors that might account for the sizable discrepancies in adolescents’ attachment relationships in the family.