Physical Growth • The course of physical growth • Growth curves and physical growth • Distance curve • Velocity curve • Growth curves for organs • Changes in body proportions • Cephalo-caudal development • Proximo-distal development • Continuous versus episodic growth • Psychological reactions to physical growth • Puberty – reactions to physical maturation • Reactions of boys/men • Reactions of girls/women • Early versus late maturation • Effects on adolescent adjustment • Why is maturational timing important?
Distal Growth Curves • Distal growth curves: • Plots the growth of particular body dimension each year • Can determine interesting facts about physical growth • Plot boys and girls separately, see sex differences • Ex. In infancy, height and weight comparable • Age 11, see reversal in trend – girls shoot past boys • Advantage short-lived – reverses again by 14
Velocity Curve • Velocity curve: • Plots absolute growth at yearly intervals • Better than distance curve at identifying timing of growth spurts • See same graph of height gain • Timing of growth spurts much more evident
Growth Curves for Body Organs • Velocity curves for body organs: • Plotted in terms of percent of adult size • See variety of patterns for different organs • Brain and skull mature quite quickly • Genital more slowly, then growth spurt in adolescence • Lymphoid system overgrows, then shrinks
Changes in Body Proportions • Cephalo-caudal development: • Growth occurs from the head downwards • In infancy upper part of body grows first • Lower part of body catches up in adolescence • Proximo-distal development: • Growth begins near center of body axis • Trunk of body grows before upper arms • Upper arms grow before lower arms and hands
Psychological Reactions to Physical Growth • Puberty: The transition to adulthood • Physical changes and development • Psychological impact of puberty • Girl reactions to first menarche • Early studies • Importance of advance information • Boys reaction to first spermarche • The importance of early versus late maturation • Berkeley study of maturational timing • Early versus late maturing boys • Early versus late maturing girls • Explanations for maturational timing effects