Developing Through the Lifespan

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Alicia Chen
Chapter 4: Developing Through the Lifespan
Introduction
• developmental psychologists – study physical, cognitive, and social changes throughout the lifespan; discern commonalities • developmental psychology focuses on 3 issues:
o Nature/nurture: how do genetic inheritance and experience influence development? o Continuity/stages: is development a gradual, continuous process, or a sequence of separate stages o Stability/change: do our early personality traits persist through life, or do we become different persons as we age? Prenatal Development and the Newborn

Conception
• Ovary releases an egg, and 200 million sperm come toward it; woman born with all immature eggs ever needed, whereas men produce sperm starting at puberty, and slowing production as age increases • Sperm that make it to the egg release digestive enzymes that eat away at egg’s protective coating, allowing sperm to penetrate, which then causes the egg to block out all others • In 12 hours, egg and sperm nucleus fuse

Prenatal development
• Less than half of all zygotes (fertilized eggs) survive past 2 weeks • Within the first week (when zygote is 100 cells large), cells began to differentiate (specialize in structure & function) • After 10 days – zygote attaches to mother’s uterine wall - outer part attaches to wall, which forms the placenta; inner cells become embryo (2 weeks through month 2) • Next 6 weeks – organs begin to form and function; heart begins to beat • By 9 weeks – is called a fetus; 6th month – organs (stomach) formed and functional to allow premature fetus a chance of survival, responsive to sound, prefer mother’s voice to another woman or father’s • Placenta transfers nutrients and oxygen, screens harmful substances, though it can admit teratogens: harmful agents (viruses, drugs) which cause mother-to-baby transfer of AIDS, heroin addiction, nicotine; alcohol depresses activity in both nervous systems • Fetal alcohol syndrome (FAS): small, misproportioned head and lifelong brain abnormalities ( mental retardation; caused by common maternal drinking (40% of alcoholic mothers have FAS babies) • Stress leads to offspring w/ delayed motor development, increased emotionality, learning deficits, and alterations in neurotransmitter systems associated w/ human psychological disorders (depression) The competent newborn

• Rooting reflex: baby’s tendency, when touched on the cheek, to turn towards touch, open mouth, and search for nipple • Babies born preferring sights & sounds that facilitate social responsiveness – turn heads to human voices, prefers drawings of human faces • Baby brains stamped w/ smell of mothers’ body, familiar w/ voice Infancy and Childhood

Physical development
Brain Development
• Brain development finishes in the womb, but nervous system development occurs after birth; from ages 3-6 it occurs rapidly in the frontal lobe (rational planning) • Association areas (thinking, memory, language) – last brain areas to develop • Fiber pathways supporting language and agility proliferate into puberty, after which a pruning process shuts down extra connections while strengthening others • Human experience maturation – biological growth processes that enable orderly changes in behavior, relatively uninfluenced by experience Motor Development

• Babies roll over before they sit unsupported, crawl before walk – reflect a maturing nervous system • Most babies walk by age 15 months, though this may be influenced a bit by environmental influences (back-to-crib associated w/ later crawling) • Genes play a major role; biological maturation (development of cerebellum) creates readiness to learn walking, bowel & bladder control Maturation and Infant Memory

• “infantile amnesia” before age 3: average age of earliest conscious memory is 3.5 years • Memories of preschool years are few because we...
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