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ABSTRACT Given the foundational nature of infant visual attention and potential cascading effects on later development, studies of individual variability in developmental trajectories in a normative sample are needed. We longitudinally tested newborns (N= 77) at 1–2 and 3–4 weeks, then again at 2, 4, 6, 8 and 14 months of age, assessing individual differences in their attention. Newborns viewed live stimuli (facial gesturing, rotating disk), one at a time, for 3 min each. Older infants viewed a 10‐s side‐by‐side social–nonsocial video (people talking, rotating disk). We found short‐term developmental stability of interindividual differences in infants’ overall, social, and nonsocial attention, within the newborn period (1–4 weeks), and within the later infancy period (2–14 months). Additionally, we found that overall attention, but not social and nonsocial attention, was developmentally stable long term (newborn through 14 months). This novel finding that newborn overall attention predicts later overall attention through the first year suggests a robust individual difference. This study is a first step toward developing individual difference measures of social and nonsocial attention. Future studies need to understand why newborns vary in their attention and to identify the potential impact of this variability on later social and cognitive development.
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Infants' salivary oxytocin and positive affective reactions to people
Oxytocin is a neuropeptide positively associated with prosociality in adults. Here, we studied whether infants' salivary oxytocin can be reliably measured, is developmentally stable, and is linked to social behavior. We longitudinally collected saliva from 62 U.S. infants (44 % female, 56 % Hispanic/Latino, 24 % Black, 18 % non-Hispanic White, 11 % multiracial) at 4, 8, and 14 months of age and offline-video-coded the valence of their facial affect in response to a video of a smiling woman. We also captured infants' affective reactions in terms of excitement/joyfulness during a live, structured interaction with a singing woman in the Early Social Communication Scales at 14 months. We detected stable individual differences in infants' oxytocin levels over time (over minutes and months) and in infants' positive affect over months and across contexts (video-based and in live interactions). We detected no statistically significant changes in oxytocin levels between 4 and 8 months but found an increase from 8 to 14 months. Infants with higher oxytocin levels showed more positive facial affect to a smiling person video at 4 months; however, this association disappeared at 8 months, and reversed at 14 months (i.e., higher oxytocin was associated with less positive facial affect). Infant salivary oxytocin may be a reliable physiological measure of individual differences related to socio-emotional development.
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- Award ID(s):
- 1653737
- PAR ID:
- 10539366
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Hormones and Behavior
- Volume:
- 164
- ISSN:
- 0018-506X
- Page Range / eLocation ID:
- 105579
- Subject(s) / Keyword(s):
- Hormone Physiology Positive sociality Social interaction Longitudinal
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.yhbeh.2024.105579
