Читать книгу Lifespan Development - Tara L. Kuther - Страница 235

Maturation plays a very strong role in motor development. Preterm infants reach motor milestones later than do full-term infants (Gabriel et al., 2009). Cross-cultural research also supports the role of maturation because around the world, infants display roughly the same sequence of motor milestones. Among some Native Americans and other ethnic groups around the world, it is common to follow the tradition of tightly swaddling infants to cradleboards and strapping the board to the mother’s back during nearly all waking hours for the first 6 to 12 months of the child’s life. Although this might lead one to expect that swaddled babies will not learn to walk as early as babies whose movements are unrestricted, studies of Hopi Indian infants have shown that swaddling has little impact on when Hopi infants initiate walking (Dennis & Dennis, 1991; Harriman & Lukosius, 1982). Such research suggests that walking is very much maturationally programmed. Other evidence for the maturational basis of motor development comes from twin studies. Identical twins, who share the same genes, have more similarities in the timing and pace of motor development than do fraternal twins, who share half of their genes (Fogel, 2007; Wilson & Harpring, 1972). Samples of young children in the United States show no ethnic or socioeconomic status differences in gross motor skill such as running, hopping, kicking, and catching (Kit, Akinbami, Isfahani, & Ulrich, 2017).