5.1 Myers Psychology

Prenatal Development and the Newborn (507-511)

I. Conception

  1. Overview of the Conception Process

    • Release of mature egg from ovary

    • Sperm's journey to fertilize egg

    • One sperm successfully fertilizes the egg after releasing enzymes

    • Fusion of sperm and egg nuclei

  2. Key Concepts

    • Zygote: Fertilized egg, develops into embryo

    • Sperm Production in Men: Continuous from puberty onward

    • Egg Production in Women: Limited, released once a month from puberty

II. Prenatal Development

  1. Early Stages of Development

    • Zygote (Fertilized Egg): Survives the first 2 weeks

    • Cell division and differentiation: Identical cells become specialized

    • The embryo (after 10 days) attaches to the uterine wall

    • Development of the placenta: Transfers nutrients and oxygen

  2. Development Timeline

    • Weeks 3-6: Organ formation begins (e.g., the heart starts beating)

    • Week 9: Embryo becomes a fetus

    • By the 6th month: the Fetus has developed enough to survive if born prematurely.

  3. Genetic & Environmental Influences

    • Teratogens: Harmful agents (e.g., viruses, drugs) that can pass through the placenta

      • Example: Fetal Alcohol Syndrome (FAS) caused by maternal alcohol consumption

      • Epigenetic effects: Alcohol can affect gene expression

III. The Competent Newborn

  1. Newborn Reflexes and Abilities

    • Rooting Reflex: Baby turns head toward touch, opening mouth to seek food

    • Sucking Reflex: Baby automatically begins sucking when they find a nipple

  2. Sensory and Cognitive Abilities

    • Babies are born predisposed to respond to sensory stimuli, such as sight and sound.d

    • Newborns are especially attuned to faces, voices, and smells (e.g., recognition of mother's scent)

  3. Research on Infant Abilities

    • Habituation: Decreased response to repeated stimuli; used to measure infant preferences

      • Example: Visual-preference test shows infants can distinguish between familiar and novel images (e.g., cat vs. cat-dog hybrid)

  4. Prenatal Learning

    • Fetuses learn in the womb by adapting to external stimuli (e.g., the sound of the  mother's voice, vibrations from external devices)

IV. Teratogens and Their Impact on Development

  1. Teratogens: Agents that can cause harm during prenatal development

    • Alcohol: Can cause birth defects, brain damage, and future behavioral problems

    • Fetal Alcohol Syndrome (FAS): Results from heavy alcohol consumption during pregnancy

    • Other Teratogens: Viruses, drugs, and environmental toxins

  2. Implications for Prenatal Care

    • Pregnant women are advised to avoid harmful substances like alcohol and certain medications to protect fetal development.t

V. Summary of Key Developmental Stages

  1. Zygote: Conception to 2 weeks

  2. Embryo: 2 to 9 weeks (organ systems begin developing)

  3. Fetus: 9 weeks to birth (continued growth and development)

Infancy and Childhood: Physical Development (513-515)

Module Learning Objectives:

  1. Describe developmental changes in brain and motor abilities during infancy and childhood.

  2. Describe how an infant’s developing brain begins processing memories.

I. Brain Development

  1. Prenatal Brain Growth:

    • In the womb, the brain forms nerve cells at an incredible rate of 250,000 per minute.

    • By birth, the brain has nearly 23 billion neurons, with overproduction during early development.

    • The cortex undergoes rapid changes, especially from ages 3 to 6 when the frontal lobes (responsible for planning and control) grow the fastest.

    • As the brain matures, it undergoes a "pruning" process, strengthening used connections and eliminating unused ones.

  2. Brain Maturation and Cognitive Growth:

    • The brain grows through both nature (genes) and nurture (experience). For example, experience and interactions shape neural networks.

    • The last brain areas to mature are association areas linked with thinking, memory, and language.

    • This maturation explains why preschoolers often develop the ability to control attention and behavior rapidly.

II. Motor Development

  1. Coordination and Physical Skills:

    • Motor development is a sequence that reflects the maturation of the nervous system.

    • Babies tend to roll over before sitting unsupported, crawl before walking, and walk before running.

    • This sequence is universal across cultures, though individual timing varies.

    • For instance, in the U.S., 25% of babies walk by 11 months, 50% by 12 months, and 90% by 15 months.

    • Genetics guide motor development, with identical twins walking nearly simultaneously.

  2. Key Factors Affecting Motor Skills:

    • Cerebellum maturation helps babies learn to walk, and muscular development is key for skills like bowel control.

    • The Back-to-Sleep position reduces Sudden Infant Death Syndrome (SIDS) but may slightly delay crawling (no effect on walking).

III. Brain Maturation and Infant Memory

  1. Infantile Amnesia:

    • Most people cannot remember events before the age of 3-4 years—this is called infantile amnesia.

    • Studies show that children aged 4-5 can remember events from earlier childhood, but those who were 3 years old have difficulty recalling details.

  2. Infant Memory Formation:

    • Research by Rovee-Collier demonstrated that infants can form memories, even as young as 2 months old.

    • Example: Babies learned to kick their legs to move a mobile and could remember this association even a month later.

    • Implicit memory (non-verbal) can form at a very early age, though explicit memory (conscious, verbal) takes longer to develop.

  3. Memory Processing in the Brain:

    • The hippocampus and frontal lobes, which are responsible for memory processing, continue to mature into adolescence.

    • Memory formation occurs even when conscious recollection of the event is absent (e.g., language learning in infancy).

IV. Summary of Key Developmental Concepts

  1. Maturation: Biological growth processes that guide changes in behavior.

  2. Motor Development: A universal sequence of physical milestones, shaped by genetic maturation and neural development.

  3. Brain Maturation and Memory: The developing brain processes and stores information before it is consciously recalled, demonstrating that memory formation starts early in infancy, though explicit memories only emerge later.

Summary:

Prenatal development begins with conception when a sperm fertilizes an egg, forming a zygote. The developing embryo attaches to the uterine wall, and during the first few weeks, the placenta forms to nourish the fetus. By the 6th month of pregnancy, the fetus is developed enough to survive if born prematurely. Throughout pregnancy, factors like teratogens (harmful substances such as alcohol and viruses) can impact fetal development, leading to conditions like Fetal Alcohol Syndrome (FAS). After birth, newborns exhibit basic reflexes (e.g., rooting and sucking) and are attuned to sensory stimuli such as voices and faces. Early in infancy, babies can begin processing memories, though they experience infantile amnesia, meaning they can't recall events before age 3 or 4. As infants grow, brain development continues, with the frontal lobes maturing most rapidly from ages 3 to 6, improving skills like attention and control. Motor development progresses in a predictable sequence, such as crawling before walking. Genetic maturation guides this process, with the cerebellum playing a critical role in movement coordination. By the time infants are toddlers, their brains and bodies have matured enough to master walking, running, and other physical skills.

Key Vocabulary:

  • Zygote: The fertilized egg that is the earliest stage of human development.

  • Placenta: An organ that transfers nutrients and oxygen from the mother to the developing fetus.

  • Teratogens: Harmful agents (e.g., alcohol, drugs, viruses) that can cause developmental damage to a fetus.

  • Fetal Alcohol Syndrome (FAS): A condition in children caused by heavy alcohol consumption during pregnancy, leading to brain damage and developmental issues.

  • Infantile Amnesia: The inability to remember events from early childhood, typically before age 3-4.

  • Pruning: The process of eliminating unused neural connections while active ones are strengthened.

  • Cerebellum: The brain structure responsible for motor coordination and movement skills.

  • Motor Development: The progression of physical skills, such as rolling over, sitting, crawling, and walking, influenced by maturation and genetics.

  • Frontal Lobes: Brain regions responsible for planning, decision-making, and controlling attention and behavior, which develop rapidly during early childhood.