Behavioral inhibition, heart period, and respiratory sinus arrhythmia: an attachment perspective.

This study shows that relations between behavioral inhibition and cardiac activity may be clarified by identifying attachment status, whereas relations between security of attachment and cardiac activity may be clarified by identifying inhibition status. Assessments at 4.5 years (N = 126) included heart period (HP), respiratory sinus arrhythmia (RSA), behavioral inhibition (BI), and security of attachment. There was no main effect of BI status (Low, Medium, High) on either HP or RSA. Instead, it was only the Secure children who showed the predicted relation between low BI and high HP or RSA, with the Low BI-Secure group having significantly higher HP than either the High BI-Secure or the Low BI-Insecure groups. Turning to attachment, both HP and RSA increased significantly from an assessment during separation from mother to an assessment 3 min after reunion. The only subgroups showing a significant increase in HP, however, were those with both secure attachment and an absence of high BI.