Human Development Notes

Studying Development

Physical Development

Cognitive Development

Socio-emotional Development

Moral Development

Personality Development

Chapter 8: Human Development

UPY1001/4 & UPY201 INTRODUCTION TO PSYCHOLOGY

Development Psychology

• Studies age-related changes in behavior and mental processes from conception to death.

Theoretical Issues Guiding Research in Human Development Psychology

1. Nature (biology) vs Nurture (learning)
   • Nature - born with a particular genetic predisposition (eye color) or the influence of our inherited characteristic on our personality, physical growth, intellectual growth, and social interactions.
   • Nurture - the influence of the environment on personality, physical growth, intellectual growth, and social interactions.
   • Almost all psychologists believe that nature and nurture interact to influence development, but there are also debates over the years about this issue.
2. Continuity vs Stages
   • Continuity – continuous development with new abilities, skills, and knowledge. (e.g.: adult thinking differs from child). Added according to age.
   • Stages(discontinuity) – behavior is qualitatively different at each stage of development (the behavior occurs in a fixed sequence).

Development Psychology

3. Stability (maintained) vs changes

   • Stability (maintained) - means a person’s way of thinking stays the same as they grow older.

   • Change - means a person’s behavior or way of thinking changes.

   • Nature vs Nurture

   • Continuity vs Stages

   • Stability vs Changes

Research Method

To study developmental researchers use the cross-sectional, longitudinal, and cross-sequential approaches:

• Cross-sectional design:
  • Different participants of various ages are compared at one point in time to determine age-related differences.
• Longitudinal design:
  • The same participants are studied at various ages to determine age-related changes.
• Cross-sequential design:
  • Different participants of various ages are compared at several points in time to determine both age-related differences and age-related changes.

Physical Development

The beginning of human development starts with the fertilization of the mother’s ovum by the father’s sperm.

The average human gestational period is 38-40 weeks.

Because of the different changes that occur during these 40 weeks, developmental researchers divide this time frame into three phases;

• Germinal stage (from conception to 2 weeks).
  • The earliest stage of gestation
  • First two weeks after fertilization, during which the zygote moves down to the uterus and begins to implant in the lining.
• Embryonic stage (3 to 8 weeks)
  • Embryo is the name for the developing organism from two weeks to eight weeks after fertilization.
  • Early stage of development
  • Is characterized by the formation of the major organs and system, including the respiratory, excretory, cardiovascular, and nervous system.
  • Consequently, this stage of prenatal development is very precarious.
  • Genetic abnormalities usually appear at this time.

Physical Development

• The Fetal stage (3 months - birth)
  • The organism in this stage is referred to as a fetus.
  • Although the fetus's major features are basically complete by 12 weeks, the fetus continues to grow, differentiate, and develop until birth.
  • The latter stage of prenatal development.

Stages in Human Embryonic and Fetal Development

• 3 weeks:
  • Organogenesis begins with neural tube formation, seen here as enlarged crests that delineate the neural groove from which the spinal cord and brain develop.
  • LENGTH-0.25 cm $(\frac{1}{10})$ in).
• 4 weeks:
  • A pumping heart, somites, developing eye, arm, and leg buds are evident. The embryo has a long tail, gill arches, and a relatively enormous head.
  • LENGTH-0.7 cm $(\frac{1}{3})$ in).
• 5 weeks:
  • Internal organ development is well underway. Fingers are faintly suggested. Fetal circulatory system is evident and body stem is now an umbilical cord.
  • LENGTH-1.2 cm $(\frac{1}{2})$ in)

Stages in Human Embryonic and Fetal Development (Continued)

• 2.5 months:
  • The fetus, seen here floating in the amniotic cavity, now has all major organ systems. The umbilical blood vessels and placenta are well defined. Tail and gill arches have disappeared.
  • LENGTH-3 cm $(1 \frac{1}{2})$ in).
• 5 months:
  • The fetus looks very much as she will at birth. Bone marrow is assuming more of the blood-producing duties. Mother begins to feel fetal movements, even hiccupping.
  • LENGTH 25 cm (10 in).
• 5.5 months:
  • The vernix caseosa is accentuated by a groove the fetus has scraped away with its thumb. Internal organs now occupy their permanent positions (except testes in males).
  • LENGTH-30 cm (12 in).

Physical Development: Hazards to Prenatal Development

Maternal Factors and Possible Effects:

• Malnutrition:
  • Low birth weight, malformations, less developed brain, greater vulnerability to disease.
• Stress exposure:
  • Low birth weight, hyperactivity, irritability, feeding difficulties.
• Exposure to X-rays:
  • Malformations, cancer.
• Legal and illegal drugs:
  • Inhibition of bone growth, hearing loss, low birth weight, fetal alcohol syndrome, mental retardation, attention deficits in childhood, and death.
• Diseases:
  • German measles (rubella), herpes, AIDS, and toxoplasmosis: Blindness, deafness, mental retardation, heart and other malformations, brain infection, spontaneous abortion, premature birth, low birth weight, and death.

Physical Development: Hazards to Prenatal Development

• Teratogens: Environmental agents that cause damage during prenatal development by crossing the placental barrier.
• Categories of teratogens include:
  • Legal and illegal drugs (alcohol, nicotine, damage in prenatal development, low IQ).
  • Diseases and malnutrition.
  • Exposure to X-ray and stress exposure.
• Fetal alcohol spectrum disorders (FASDs): a group of conditions caused by a mother consuming alcohol during pregnancy, in which a combination of physical, mental, and behavioral problems may be present.

Prenatal Development (from conception to birth of the baby is approximately 9 months in humans)

• Fertilization, the zygote, and twinning
  • Egg and sperm unite through the process of fertilization, resulting in a single cell (zygote) that has 46 chromosomes.
  • Through mitosis, the zygote begins to divide into two cells, then four, etc., until the baby is formed.
  • Alterations in mitosis can result in twins or multiples.
• Germinal period (2-week period following fertilization)
  • Zygote continues dividing and moving toward the uterus; the placenta and umbilical cord also develop during this time.
  • Cell differentiation is the process that results in specialized cells for all of the various parts of the body.
• Embryonic period (2 weeks after conception to 8 weeks)
  • Once attached to the uterus, the developing organism is called an embryo.
  • Cell specialization continues to occur, resulting in the preliminary versions of various organs.
  • The embryo is vulnerable to hazards such as diseases and substances ingested by the mother as it receives nourishment through the placenta.
• Fetal period (from about 8 weeks to birth)
  • The developing organism is now called a fetus; time of tremendous growth and development.
  • Organs continue to develop and become fully functional.
  • Full-term birth occurs around the end of the 38th week.
  • Miscarriages (spontaneous abortions) are most likely to occur in the first three months.

Physical Development: Brain Development

• As a child grows, neurons grow in size and the number of dendrites and axons increase.
• The sense of smell, taste, touch, and hearing are quite developed at birth.
• The sense of vision is poorly developed at birth.

Cognitive Development

• The development of thinking, problem-solving, and memory.

Cognitive Development

• Jean Piaget has demonstrated the unique cognitive processes of children.
• He believed that children are driven toward knowledge because of their biological need for adaptation to the environment.
• Piaget didn’t do lab experiments — instead, he used natural observation and interviews, often with his own children and other children.
• Schemas: mental concepts formed by children as they experience new situations and events.
• Assimilation: the process of understanding new things in terms of schemas they already possess.
• Accommodation: The process of altering or adjusting old schemas to fit new information and experiences.

Cognitive Development

• Two-year-old Jocelyn has learned the schema for "dog" from her picture books.
• Jocelyn sees a cat and calls it a "dog." She is trying to assimilate this new animal into an existing schema.
• Her mother tells her, "No, it's a cat."
• Jocelyn accommodates her schema for 4-legged animals and continues to modify that schema to include different kinds of dogs and cats in the neighborhood.

Cognitive Development

Cognitive Development

• Sensorimotor stage: Piaget’s first stage of cognitive development, in which the infant uses its senses and motor abilities to interact with objects in the environment
  • Birth to 2
  • Object permanence: the knowledge that an object exists even when it is not in sight
  • Symbolic thought begins (mentally represent objects or events)

Cognitive Development

• Preoperational stage: Piaget’s second stage of cognitive development, in which the preschool child learns to use language as a means of exploring the world, from ages 2-7
  • Egocentrism
    • The inability to see the world through other people’s view
    • They believe everyone sees and feels the same way they do.
  • Centration
    • The child focuses on only one part of an object or situation and ignores the rest.
  • Conservation
    • Conservation means knowing that something stays the same (like amount, volume, or number) even when its appearance changes.
  • Irreversibility
    • The child cannot mentally reverse an action or process.

Cognitive Development

Tests of Various Types of Conservation

Cognitive Development

• Concrete operations stage: third stage of cognitive development in which the school-age child becomes capable of logical thought processes but is not yet capable of abstract thinking.
• Formal operations: Piaget’s last stage of cognitive development in which the adolescent becomes capable of abstract thinking.

Piaget's Four Stages of Cognitive Development