In Touch with the Heartbeat: Newborns' Cardiac Sensitivity to Affective and Non-Affective Touch

Abstract

The sense of touch is the first manner of contact with the external world, providing a foundation for the development of sensorimotor skills and socio-affective behaviors. In particular, affective touch is at the core of early interpersonal interactions and the developing bodily self, promoting the balance between internal physiological state and responsiveness to external environment. The aim of the present study is to investigate whether newborns are able to discriminate between affective touch and non-affective somatosensory stimulations and whether affective touch promotes a positive physiological state. We recorded full-term newborns' (N = 30) heart rate variability (HRV)-which reflects oscillations of heart rate associated with autonomic cardio-respiratory regulation-while newborns were presented with two minutes of affective (stroking) and non-affective (tapping) touch alternated with two minutes of resting in a within-subject design. The results revealed that non-affective touch elicits a decrease in HRV, whereas affective touch does not result in a change of HRV possibly indicating maintenance of calm physiological state. Thus, newborns showed cardiac sensitivity to different types of touch, suggesting that early somatosensory stimulation represents scaffolding for development of autonomic self-regulation with important implications on infant's ability to adaptively respond to the surrounding social and physical environment.

Keywords: affective touch; autonomic self-regulation; heart rate variability; newborns.

Figure 1

Example of experimental session: newborns’ heart rate was recorded for 10 min, alternating 2 min of resting with 2 min of tactile stimulation (affective touch vs. non-affective touch) in counterbalance order between participants.

Figure 2

Differential RMSSD score during the two tactile stimulations compared to the pre-stimulus resting period. In the affective touch condition infants’ did not show a variation of RMSSD in response to touch, whereas in the non-affective touch condition they showed a decrease in RMSSD.

Figure 3

Plot of the interaction effect between Presence of touch and Type of touch. Mean (blue dots) and standard errors (pink lines) are displayed for both resting and tactile stimulation in each experimental condition (affective vs. non-affective).

Figure 4

Plot of the interaction effect between Time and Type of touch. Mean (blue dots) and standard errors (pink lines) are displayed for each time point (pre-stimulation, stimulation and post-stimulation) in the two experimental conditions (affective and non-affective).

Figure 5

Correlation between RMSSD score during resting baseline and neonatal information, including gestational weeks (blue), birth weight (red), type of delivery (yellow) and postnatal age in hours (green).

Figure 6

Correlation between RMSSD variation during tactile stimulations and neonatal information, including gestational weeks (blue), birth weight (red), type of delivery (yellow) and postnatal age in hours (green).