Child Psychology: The Modern Science, 3e by Vasta, Haith, and Miller Paul J. Wellman Texas A&M University John Wiley and Sons, Inc. © 1999 PowerPoint  Presentation: Chapter 6 Physical Development: Birth, Motor Skills, and Growth

© 1999 John Wiley and Sons, Inc. Birth n The Perinatal period begins with birth –Birth typically occurs at 38 weeks –Birth process lasts about 16 hours (first child) –The fetus initiates the birth process by secreting chemical messages that induce rhythmic contractions of the uterus –Three stages of birth process Uterine dilation Fetus passes through the cervix Delivery of the placenta and other membranes

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 6.1 Stages of Birth

© 1999 John Wiley and Sons, Inc. “At Risk” Issues n Babies may have two different risks: –Risk for major physical malformations –At risk for developmental delays, and for cognitive and social problems n Indicators of at risk status : –Maternal and family characteristics Poor prenatal care Maternal nutrition and drug use –Physical compromise of the newborn –Newborn performance on behavioral assessment tests

© 1999 John Wiley and Sons, Inc. Newborn Assessments n Apgar exam: Focuses on 5 vital functions (e.g. heart rate, respiration, muscle tone, pain response, and skin color) n Prechtl test: Assesses 15 reflexes, alertness, and posture n Brazelton Neonatal Behavioral Assessment Scale: Assesses –Attention and social responsiveness –Muscle tone and physical movement –Control of alertness –Physiological responses to stress

© 1999 John Wiley and Sons, Inc. States of Alertness n Infant alertness varies across day and night in at least 6 different states: –Deep sleep: Eyes closed, no eye movements, regular breathing –Light sleep: Rapid eye movements, low activity level, irregular breathing –Drowsiness: Eyes are open, delayed responses to stimulation –Alert inactivity: Eyes open and bright –Alert activity: Eyes open, high activity level –Crying: Intense crying, high motor activity

© 1999 John Wiley and Sons, Inc. Sleep n Recordings of brain electrical activity (EEG) reveal that sleep-waking states change across the lifespan –Duration of sleep per night decreases with age –The percentage of time spent in Rapid Eye Movement (REM) sleep decreases with age Function of REM sleep is unknown Suggestions have been made that REM represents an internal activation process for brain neurons

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 6.2 Sleep-Waking Across the Lifespan (Figure reprinted with permission from “Ontogenetic Development of Human Sleep-Dream Cycle”, by H.P. Roffwarg, J.N. Muzio, and W.C. Dement, 1966, Science, 152, p Copyright © 1966 by the AAAS.)

© 1999 John Wiley and Sons, Inc. Newborn Reflexes n Some reflexes are evident at birth but disappear by age one; These reflexes can index the development of the infant –Rooting reflex: Tactile stimulation of the cheek elicits a head turn toward the stimulus –Palmar reflex: Pressure by an object on the palm of the infant elicits a grasping of the object –Moro reflex: Loss of head support elicits a motor sequence of embracing

© 1999 John Wiley and Sons, Inc. Motor Development n Postural development and locomotion refers to control of body trunk and legs for movement n Prehension refers to the ability to use the hands and fingers as tools for grasping n Motor skill development proceeds in –Proximodistal direction: Body parts near the center of the infant come under control before distant parts (arms before hands) –Cephalocaudal direction: Body parts near the head are controlled first

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig Development of Locomotion (Figure adapted with permission from “Early Development of Locomotion: Significance of Prematurity, Cerebral Palsy, and Sex” by R.H. Largo, L. Molinari, M. Weber, L.C. Pinto, and G. Duc, 1985, Developmental Medicine and Child Neurology, 27, pp , figure 2. Copyright © 1985 by MacKeith Press.)

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 6.6 Brain Development n Three phases of brain development: –Cell production: Neurons are produced between 10 and 26 weeks post-conception –Cell migration: Nerve cells travel from inner neural tube outward to final location –Cell elaboration: Synapses are formed, nerve cells are “pruned”

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 6.7 Cortical Function

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 6.8 Physical Growth (Figure adapted with permission from “Standards for Growth and Growth Velocity” by J.M. Tanner, R.H. Whitehouse, and M Takaishi, 1966, Archives of Disease in Childhood, 41, p 467. Copyright © 1966 by Archives of Disease in Childhood)

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 6.9 Growth Patterns (Figure adapted with permission from “Individual Patterns of Development” by N. Bayley, 1956, Child Development, 27, p. 52. Copyright © 1956 by The Society for Research in Child Development, Inc)

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