Posture and the emergence of manual skills

Abstract

In this paper, we examine how infants' natural manual and postural activities ± what they prefer and do week by week ± are related to developmental transitions in reaching skill and its neuromuscular control. Using a dense, longitudinal design, we tracked the manual and postural activities of four infants in a natural, free-play setting across the first year of life, and related these activities to two transitions in reaching as measured in a structured laboratory setting: the transition to reaching and the transition to stable reaching. Our data indicated that specific advances in the free-play setting preceded both transitions. Head and upper torso control, the ability to extend the arm and hand to a distant target, and the ability to touch and grasp objects placed nearby were all precursors to the onset of reaching, whereas sitting independently was associated with the transition to stable reaching. We also found important individual variability in when these`components' were in place, indicating that it is the ensemble of components that is essential, not the order in which they develop or the timing of their contribution. These findings suggest that subsequent experimental manipulations should be planned with respect to infants' individual constellations of skills, rather than looking at only a single precursor to change.

Sit happens: Does sitting development perturb reaching development, or vice versa?

“…In addition, we were able to determine that, in unsupported sitting, infants decrease the amount of time that arms are used for postural support as sitting advances and reaching improves (Thelen & Spencer, 1998). This change in arm use, from a postural support to increasing object manipulation, agrees with past research on developing reach (Spencer et al, 2000;Rochat, 1992) in which the infants were protected from a loss of postural control.…”

“…Spencer, Vereijken, Diedrich, and Thelen (2000) posited that sitting independently was associated with stable reaching. For example, Kamm (1995) coded the reaching and sitting progression in 5 infants from 8 weeks of age until they had one month of sitting experience.…”

The Influence of Mouthing on Infant Vocalization

“…Object mouthing emerges early in infancy and increases between 15 and 20 weeks as reaching becomes productive (Rochat, 1989;Spencer, Vereijken, Diedrich, & Thelen, 2000). Mouthing peaks between 6 and 9 months and declines between 9.5 and 15.5 months, replaced by other forms of object exploration and manipulation (Belsky & Most, 1981;McCall, 1974;Palmer, 1989;Rochat, 1989;Ruff, 1984;Ruff et al, 1992;Whyte et al, 1994;Zelazo & Kearsley, 1980).…”

“…Encountering novel information increases infants' chances of learning (Bradley-Johnson, Friedrich, & Wyrembelski, 1981;Rochat, 1989;Ruff, 1984) and contributes to cognitive and perceptual development (Bradley-Johnson et al, 1981;Ruff, 1984). Through exploration, therefore, infants play an active role in developmental change (Spencer et al, 2000).…”

Children and the Principles of Learning: Implications for Multicultural Development

“…Research suggests certain forms of learning occur via the same pathway regardless of age (e.g., Chen & Siegler, 2000;Kuhn, Garcia-Mila, Zohar, & Andersen, 1995;Siegler & Chen, 1998), whereas other styles of learning arise from multiple pathways that change over time (Spencer, Vereijken, Diedrich, & Thelen, 2000). The process of learning involves progress, inconsistent patterns of generalization, regressions, and momentary transitional approaches, as well as qualitative and quantitative changes (Amso & Casey, 2006;Schauble, 1996;Siegler, 2005).…”