Early postnatal testosterone, parental input, and social communication development in infants

Abstract

Infancy is a crucially important period for social communication development to lay its foundation. Typically developing infants attain remarkable social communication milestones during the first year of life. Delays and deficits in these milestones, on the other hand, may indicate risks for developmental challenges. Autism is one of the developmental conditions that is closely linked to social communication development. Prior studies have suggested that gender differences in social communication development as well as autism are present during the early stages of life. The present study examined two factors that may contribute to early social communication development and the gender differences: salivary testosterone during the peak of mini-puberty as well as parental responsiveness. The following hypotheses were tested: (1) girls would score higher on the social communication measures; (2) boys would have higher testosterone concentrations; (3) mothers of girls would be more responsive; (4) testosterone would correlate negatively with social communication outcomes in boys and in girls; (5) parental responsiveness would correlate positively with social communication outcomes in boys and in girls; (6) interaction effects between testosterone and maternal responsiveness in predicting social communication outcomes would be observed.

3 weekly saliva samples were collected at 1–3 months of age for testosterone assays (Stage 1). When the infants reached 12 months age (Stage 2), they were invited to participate in a laboratory session with their mothers. Maternal responsiveness during a reading task, a free play task, and a problem-solving task was measured. Social communication development was also assessed at Stage 2 using both a parent-reported checklist for identification of communication delays and autism as well as lab observation tasks. The lab observation focused on eye contact during parent-child interaction, as eye contact is a crucial aspect of social communication starting from the prelinguistic stage. Atypical eye contact is also an early diagnostic feature of autism.

116 infant boys and 83 infant girls completed data collection procedures for both time points. Significant gender differences were observed for salivary testosterone and social communication outcomes. However, no significant correlations were found between salivary testosterone and any of the social communication outcomes. Maternal responsiveness also did not significantly correlate with CSBS scores or eye contact measures. Moreover, no significant interaction effects were found between testosterone and maternal responsiveness in predicting social communication outcomes. Findings of the present study contributes to the evidence that gender differences in social communication are present early in life. While results of the present study suggest that the effects of early androgen exposure on social communication development are unlikely robust, the consistent sex differences in salivary testosterone found during the peak of mini puberty indicate that saliva sampling is a promising approach for examining the potential effects of early androgen exposure on later gender-related development. Further follow-ups of the current sample will provide insights on whether gender differences in social communication contribute to gender-differentiated maternal responsiveness later in life. Future research may also employ a multi-perspective approach to understand how different factors jointly shape social communication development.