Biology or SES? Examining the factors that impact motor development during infancy

• In Event: Poster Session 08
  In Poster Session: PS 08 Topic - Perceptual, Sensory, Motor

Abstract

Background: Motor skills are a rate-limiting factor for infant learning and consequently impact development across domains (Libertus & Needham, 2011). Therefore, it is important to understand the processes and factors that shape motor development. However, little research focuses on individual variability and its causes when examining early motor development (Libertus & Smith, 2020). Maturational factors, such as gestational age, have been examined in premature children and show long-term effects on motor development (Guimaraes & Tudella, 2015). Similarly, motor outcomes of full-term infants are influenced by typical variations in gestational age (Rose et al., 2013). These studies suggest that biological factors may shape early motor skills, but what about experience related factors such as socioeconomic status (SES)? Higher SES has been associated with increased oral and manual object exploration (Clearfield et al., 2014). However, potential interactions between biological factors and SES remain understudied. The current study fills this gap by simultaneously exploring how biological factors and SES shape infant motor development.
Method: Participants were 455 infants and their caregivers, ranging from approximately 0.5 months to 26 months of age (45.7% female). Parents completed the Early Motor Questionnaire (EMQ), a 127-item parent-report measure of gross motor (GM, 48 items), fine motor (FM, 48 items), and perception-action development (PA, 31 items). Parents also provided information about their child’s gestational age and characteristics of their family’s SES (i.e., parent education and family income).
Results: A series of linear regressions revealed a consistent effect of gestational age across motor domains, tGM(510) = 3.786, p < .001; tFM(510) = 3.148, p = .002; tPA(510) = 3.832, p < .001. Similarly, family SES predicted infant’s FM scores, t(157)=2.749, p = .007, and PA scores t(157)=2.850, p = .005. SES did not predict GM scores, but a unique effect of father education on GM scores was observed, t(157)=-2.24, p = .027. Examining potential interactions between the two domains, family SES fully mediated the effect of gestational age on perception-action scores, z = 2.18, p = .029. No mediation effect of SES was found in fine motor scores. Finally, father education partially mediated the effect of gestational age on gross motor scores, z = -2.23, p = .026.
Conclusions: Our results suggest that gestational age and family SES predict aspects of infant motor development. Mediating effects of SES suggest that the impact of a child’s environment may eventually outweigh the initial effects of biology. Our strongest mediation results were present for the development of perception-action skills. This domain has been shown to predict subsequent cognitive development (Sommerville, Woodward, & Needham, 2005). Hence, our results suggest that SES may impact a child’s cognitive development by initially influencing early motor skills. Together, these findings demonstrate that biological and experiential factors independently and in concert influence motor skill development in infancy. Future longitudinal research should examine the interrelations between these factors more closely to offer a better understanding of the mechanisms and processes that shape infant development and learning. (487/500)

Authors

• Darcy Smith, University of Pittsburgh
  Presenting Author

• Klaus Libertus, University of Pittsburgh
  Non-Presenting Author