Physical Growth

I. The course of physical growthA. Growth curves and physical growth

1. Distance curve2. Velocity curve3. Growth curves for organs

B. Changes in body proportions1. Cephalo-caudal development2. Proximo-distal development

C. Continuous versus episodic growth

II. Psychological reactions to physical growthA. Puberty – reactions to physical maturation

1. Reactions of boys/men2. Reactions of girls/women

B. Early versus late maturation1. Effects on adolescent adjustment2. 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

0 4 8 12 16 20

Age in Years

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25

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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

Continuous vs. Episodic Growth

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