Physical Maturation

Physical growth is a highly regular process, but children differ tremendously in the timing of their growth spurts. We have studied how these timing differences are related to other variables like information processing speed.

Physical Maturation

• Traditional measures of physical maturity such as x-rays of particular bones are worrisome and expensive.
• A non-invasive, practical technique exists for use with children and adolescents -- relative physical stature.
• Level of physical maturity is expressed as the ratio of present to estimated adult stature.
• This latter estimate is calculated using published formulae applied to the parents' statures and the child's sex, age, weight, and stature.
• Two children of the same age and height will have different relative statures if one is closer to his or her estimated adult height than is the other.
• Various traditional measures of physical maturity such as the skeletal age of the left hand-wrist and knee correlate significantly with RS.

Research finding using relative stature as an index of physical maturation

• Increased maturation in 5- to 8-year-olds is associated with decreased activity levels, and gender differences in activity may be, in part, the result of sex differences in maturation (Eaton & Yu, 1989).
• Information processing speed increases steadily through middle childhood, and we (Eaton & Ritchot, 1995) showed that early maturing 9- and 10-year-olds were faster on three reaction time tasks than their late-maturing age-mates.
• More mature 5- to 11-year-olds do better on some tests of phonological ability (Eaton & Speed, 1995).
• In a test of the controversial hypothesis that left-handers are maturationally delayed, we (Eaton, Chipperfield, Ritchot, and Kostiuk, 1996) found in three different samples that there was no difference between right- and left-handers.

Stature Measurement

Head Circumference Measurement

Measuring Head Circumference