Page 77 - Understanding Psychology

Figure 3.1 Newborn Reflexes
Reflexes are important in determining the health of an infant. In the grasping reflex, newborns close their fingers tightly around objects placed in their hands. What seems to be the purpose of these reflexes?
How do we measure the capabilities of newborn infants who cannot speak or understand the questions of curious psychologists? One rea- sonable way to answer these questions is to take advantage of the things infants can do. What they can do is suck, turn their
heads, look at things, cry, smile, and show signs of
surprise or fright. The vigor of an infant’s sucking, the
patterns of eye movements, and expressions of plea-
sure and displeasure are all closely tied to how the
infant is being stimulated. By measuring these behav-
iors while stimulating the infant in different ways, we
can infer how the infant perceives the world.
PHYSICAL DEVELOPMENT
Infants on average weigh 7.3 pounds at birth. Some infants can weigh as much as 20 or 25 pounds by the end of the first year. At birth, 95 percent of infants are between 5.5 and 10 pounds and are 18 to 22 inches in length. In the space of two years, the grasping, rooting, searching infant will develop into a child who can walk, talk, and feed herself or himself. This transformation is the result of both maturation and learning.
?Did You Know? Did You Know?
SIDS Infants have been known to quietly and mysteriously die in their sleep. Physicians call this “sudden infant death syndrome,” or SIDS. SIDS takes more lives in the first year than any other cause of infant death. We do not know why SIDS happens. One theory suggests that it results from a failure in the infant’s central nervous system in learning how to turn a reflex into a voluntary action. That is, the infant fails to learn to keep passages open for breathing. There is no known way to predict or prevent SIDS. Recent studies report a decreased incidence of SIDS when the infant is positioned on the sides or back to sleep instead of on the stomach.
Chapter 3 / Infancy and Childhood 63