Examining Links Between Infant Parasympathetic Regulation during the Still-Face Paradigm and Later Callous-Unemotional Traits.

Although research suggests that callous-unemotional (CU) traits are underpinned by deficits in social affiliation and reduced sensitivity to threat, there has been little investigation of the biophysiological regulatory mechanisms underlying these processes in infancy. The current study uses data from the Durham Child Health and Development Study (DCHD; n = 206) to examine whether and how the combination of infants' behavioral reactivity and levels of respiratory sinus arrhythmia (RSA), an indicator of parasympathetic nervous system functioning, during the still-face episode of the still-face paradigm at 6 months differentiates risk for CU traits and oppositional defiant behaviors (ODD) at age 3 years, as well as whether these relations vary by children's attachment security. Results indicate that reduced negative affect during the still-face episode at 6 months predicts higher CU traits (B = -0.28, β = -0.27, p = 0.003) and ODD (B = -0.35, β = -0.24, p = 0.007) at 3 years. Results also show that comparatively lower RSA, i.e. engaged parasympathetic system, predicts higher CU traits (B = -0.10, β = -0.34, p = 0.013), but not ODD. Tests of moderation suggest the combination of blunted negative affect but comparatively lower RSA levels during a social stressor constitutes risk for later CU traits for children who are also insecurely attached (simple slope = -0.70, t = 2.88, p = 0.006 at -1 SD). Findings contribute to our understanding of the complex and interactive risk processes which precede the development of CU traits.