Digit Ratio (2D:4D) and Attachment Styles in Middle Childhood: Indirect Evidence for an Organizational Effect of Sex Hormones

Abstract

Sex differences in attachment are absent during infancy and early childhood, emerge in middle childhood with self-reports and doll-play tasks, and persist into adulthood, when they are most reliably detected in romantic attachment styles. In our previous work, we hypothesized that sex differences in attachment develop under the influence of adrenal androgens during the transition form early to middle childhood, following activation of hormone-sensitive neural pathways organized by prenatal and early postnatal exposure to sex hormones. In this study we tested the association between the right-hand 2D:4D digit ratio (a marker of early exposure to androgens and estrogen) and sexually differentiated dimensions of attachment in middle childhood assessed with the Coping Strategies Questionnaire (CSQ). In a sample of 285 Italian children aged 8-10 years, females scored lower in avoidance and higher in preoccupation, while no significant sex differences were observed in felt security. Consistent with our predictions, higher (feminized) digit ratios were significantly associated with lower avoidance and higher preoccupation scores in both males and females. In contrast, there was no significant association between digit ratio and felt security in either sex. These results corroborate the hypothesis that sex differences in attachment reflect the activation of sexually differentiated pathways organized in early development, and for the first time implicate sex hormones in the development of individual differences in attachment styles.

Lower Digit Ratio (2D:4D) Indicative of Excess Prenatal Androgen Is Associated With Increased Sociability and Greater Social Capital

“…Although we found that low 2D:4D in men is associated with higher trait sociability and possibly more social bonds to rely on, there is evidence for a more avoidant attachment style (Del Giudice and Angeleri, 2016) and lesser quality of relationships in people with low 2D:4D (Knickmeyer et al, 2005). Furthermore, intimate partner violence is actually higher in low 2D:4D men (Romero-Martínez et al, 2013).…”

Attachment in Middle Childhood: An Evolutionary-Developmental Perspective

“…In particular, I hypothesized that the activational effects of adrenal androgens would interact with the organizational effects of prenatal sex hormones to determine both individual and sex differences in attachment styles (Del Giudice, ). A recent study provided initial empirical support for this hypothesis (Del Giudice & Angeleri, ). In a sample of 285 Italian children aged 8 to 11 years, avoidant and preoccupied attachment styles were assessed with the Coping Styles Questionnaires (CSQ; Finnegan, Hodges, & Perry, ).…”

Thou Shalt Not Bear False Witness Against Null Hypothesis Significance Testing

“…For an illustrative example, consider the search for behavioral correlates of the 2D:4D ratio. Many studies have reported significant (sometimes highly significant) correlations with aggression (see Hönekopp & Watson, 2011) and other behavioral measures in males and/or females (e.g., Del Giudice & Angeleri, 2016; Fink, Manning, & Neave, 2004; Manning & Fink, 2008; Millet & Dewitte, 2006; Ranson, Stratton, & Taylor, 2015; Richards, Stewart-Williams, & Reed, 2015), which again means that sample correlations were larger than one would expect in a sample from a population in which the variables are unrelated. Looking at the magnitude of the correlations (when these were reported) reveals that those that were significant were sometimes as low as .08 and hardly ever larger than .3, with very little (if any) theoretical value or practical utility.…”