• The study of physical, cognitive, and social changes throughout the life cycle.
Three Major Problems
• Nature/Nurture: How do genetic inheritance (our nature) and experience (the nurture we receive) influence our development? • Continuity/Stages: Is development a gradual, continuous process like riding an escalator or does it proceed through a sequence of separate stages, like climbing rungs on a ladder? • Stability/Change: Do our early personality traits persist through life or do we become a different person as we age?
• Sperm, released during intercourse, approach the egg cell, which is 85000 times its own size and only a handful make it to the egg. The ones that do make it to the egg release a digestive enzyme that dissolves the egg cell’s outer coating, allowing for penetration, but when one sperm cell begins to penetrate the egg’s surface blocks out all other sperm. • Around the sperm, fingerlike projections sprout to pull the sperm in. IN less than 12 hours, the egg nucleus and the sperm nucleus fuse together. Out of 200 million sperm, one has fused with a particular egg to make a baby.
• Zygote – the fertilized egg. It enters a two week period of rapid cell division and develops into an embryo. • Embryo – the developing human organism from about two weeks after fertilization through the second month. • Fetus – the developing human organism from nine weeks after conception to birth.
Genetic and environmental factors affect the development of a child at the prenatal stage. • The placenta transfers nutrients and oxygen from the mother to the fetus. The placenta also aids in keeping harmful substances from the fetus, but some slip in. • Teratogens, agents like chemicals and viruses, slip through the placental screen and can cause harm to the fetus. For example, if the mother has AIDS or is a heroin addict, the baby can become a heroine addict or have AIDS. • Alcohol fails to be safe as well. Even with a light drink, alcohol enters the bloodstream of the mother and depresses activity in both of their central nervous systems. • One in 150 babies will be diagnosed with Fetal Alcohol Syndrome, which exhibits physical and cognitive abnormalities in children. It sometimes includes noticeable facial disproportions. • Stress has also been seen, in mothers, to negatively affect fetuses. Stressed mothers often have offspring who increased emotionality, learning disabilities, delayed motor development, and alterations in neurotransmitter systems associated with psychological disorders. Newborn Abilities
• The rooting reflex – a baby’s tendency when touch on the cheek, to turn toward the touch, open the mouth and search for the nipple. • Habituation – As infants gain familiarity with repeated exposure to a visual stimulus, their interest wanes and they look away sooner. • Newborns’ rapidly developing senses of sight and hearing seem turned to social events. • To recognize a new stimulus as different, an infant must remember the old stimulus, which indicates a simple form of learning.
• A newborn infant is born with most of the brain cells that he/she will ever have, but the infant’s nervous system still must undergo a rapid growth spurt. From ages three to six, most growth is concentrated in the frontal lobes, which allow for rational planning. The association areas are the last to develop, and they enable thinking, language, and memory. Through puberty, language and agility abilities continue to grow, but a pruning process soon occurs, which shuts down excess connections and strengthens other connection. When not interrupted by abuse or deprivation, maturation- the biological sequence of growth process that is responsible for our similarities- guides infants along the same course of developmental...