Developing Through the Lifespan
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
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