Parenting behaviors and vagal tone at six months predict attachment disorganization at twelve months

The authors investigated the relationships among parenting behaviors, infant vagal tone, and subsequent attachment classification. Vagal tone was assessed among 6-month olds (n=95) during the still-face paradigm (SFP) via respiratory sinus arrhythmia (RSA), while attachment security and disorganization were measured at 12 months during the strange situation procedure (SSP). Infants demonstrating higher levels of RSA during the normal interaction and reunion episodes of the SFP whose mothers were also rated as negative-intrusive exhibited higher levels of attachment disorganization at 12 months, while infants with lower RSA and mothers who were negative-intrusive did not exhibit higher levels of disorganization. These results suggest that high levels of RSA may not be adaptive within the context of negative-intrusive parenting.