Foundations of Developmental Psychology: Genetics, Prenatal Development, and Early Life

2.1 Nature vs. Nurture

Introduction

The nature vs. nurture debate explores the relative contributions of genetic inheritance (nature) and environmental factors (nurture) to human development. Understanding this interaction is fundamental in psychology.

• Nature: Refers to genetic or hereditary influences on behavior and development.

• Nurture: Refers to environmental influences, including upbringing, culture, and personal experiences.

• Heredity: The passing of traits from parents to offspring through genes.

• Environment: All external factors affecting an individual, from prenatal conditions to social and cultural influences.

• Example: Intelligence is influenced by both genetic factors (nature) and educational opportunities (nurture).

2.2 Molecular Genetics

Introduction

Molecular genetics examines the structure and function of genes at a molecular level and how they influence behavior and development.

• Eugenics: A now-discredited movement aimed at improving genetic quality through selective breeding.

• Molecular Genetics: The study of the structure and function of genes at a molecular level.

• Chromosomes: Thread-like structures made of DNA that contain genes.

• Gene: A segment of DNA that codes for a specific protein or function.

• DNA: Deoxyribonucleic acid, the molecule that carries genetic information.

• Mutations: Changes in the DNA sequence that can lead to genetic variation or disorders.

• Inheritance: The process by which genetic information is passed from parents to offspring.

  • Expressed: Traits that are physically shown.

  • Dominant: An allele that masks the effect of a recessive allele.

  • Recessive: An allele whose effects are masked by a dominant allele.

  • Genotype: The genetic makeup of an individual.

  • Phenotype: The observable characteristics of an individual.

  • Allele: Different forms of a gene.

• Polygenic Inheritance: Traits controlled by two or more genes (e.g., height, skin color).

• Pleiotropic Inheritance: A single gene influences multiple traits.

• Example: Sickle cell anemia is caused by a mutation in a single gene, while height is influenced by many genes.

2.3 Behavioral Genetics

Introduction

Behavioral genetics studies the role of genetics and environment in shaping behavior, often using twin and adoption studies.

• Behavioral Genetics: The field that examines the influence of genetics and environment on behavior.

• Twin Studies: Compare identical (monozygotic) and fraternal (dizygotic) twins to assess genetic influence.

• Adoption Studies: Compare adopted children to their biological and adoptive parents to separate genetic and environmental effects.

• Monozygotic Twins: Identical twins from a single fertilized egg, sharing 100% of their genes.

• Dizygotic Twins: Fraternal twins from two different eggs, sharing about 50% of their genes.

• Passive Gene-Environment Interaction: Parents provide both genes and environment to their children.

• Example: Studies show that both genetics and environment contribute to the development of intelligence and personality.

2.4 Prenatal Diagnostic Testing

Introduction

Prenatal diagnostic testing involves procedures to detect genetic or developmental disorders in a fetus before birth.

• Invasive Testing: Procedures that involve entering the uterus (e.g., amniocentesis, CVS).

• Noninvasive Testing: Procedures that do not involve entering the uterus (e.g., ultrasound).

• Ultrasound: Uses sound waves to create images of the fetus.

• Chorionic Villus Sampling (CVS): A test where a sample of placental tissue is taken for genetic analysis.

• Amniocentesis: A test where a sample of amniotic fluid is taken to test for genetic disorders.

• Example: Amniocentesis can detect Down syndrome and other chromosomal abnormalities.

2.5 Contexts of Development

Introduction

Development occurs within multiple contexts, including biological, social, and environmental systems.

• Maturation: The process of development in which an individual matures or reaches full functionality.

• Urie Bronfenbrenner: Developed the Bioecological Theory of development.

• Bioecological Theory: Proposes that development is influenced by different types of environmental systems.

  • Microsystem: Immediate environment (family, school).

  • Mesosystem: Interactions between microsystems.

  • Exosystem: Indirect environment (parent's workplace).

  • Macrosystem: Cultural and societal influences.

  • Chronosystem: Changes over time affecting development.

• Example: A child's development is affected by family, school, community, and cultural values.

2.6 Prenatal Development

Introduction

Prenatal development covers the stages from conception to birth, including the formation and growth of the embryo and fetus.

• Female Reproductive System: Understanding the structure and function is essential for studying prenatal development.

• Trimesters: Pregnancy is divided into three trimesters, each with distinct developmental milestones.

• Stages of Prenatal Development:

  • Germinal Stage: First two weeks after conception; rapid cell division and implantation.

  • Embryonic Stage: Weeks 3-8; major organs and structures begin to form.

  • Fetal Stage: Week 9 to birth; growth and maturation of tissues and organs.

• Infertility: The inability to conceive after one year of unprotected intercourse.

• Fertilization: The union of sperm and egg to form a zygote.

• In Vitro Fertilization (IVF): A process where eggs are fertilized outside the body and implanted in the uterus.

• Embryo: The developing organism from conception to the end of the eighth week.

• Critical Period: A specific time during development when certain events must occur for normal development.

• Organogenesis: The formation of organs during the embryonic stage.

• Example: Exposure to teratogens during the embryonic stage can cause birth defects.

2.8 Stages of Childbirth

Introduction

Childbirth is a complex process divided into distinct stages, each with specific physiological events.

• Preparing for Childbirth: Includes prenatal care and education.

• Obstetrician, Midwife, Doula: Professionals who assist with childbirth.

• Braxton Hicks Contractions: Irregular, usually painless contractions that occur before true labor.

• Signs of Labor: Include regular contractions, water breaking, and cervical dilation.

• Stages of Labor:

  • Stage 1: Early, active, and transition phases; cervix dilates.

  • Stage 2: Delivery of the baby.

  • Stage 3: Delivery of the placenta.

• Birthing Locations: Hospitals, home, birthing centers.

• Example: Epidural anesthesia is commonly used for pain relief during labor.

2.9 Health Outcomes & Risks

Introduction

Various health risks can affect newborns and infants, some of which are preventable with proper care.

• Fetal Alcohol Syndrome (FAS): A condition caused by maternal alcohol consumption during pregnancy, leading to physical and cognitive impairments.

• Neonatal Abstinence Syndrome (NAS): Withdrawal symptoms in newborns exposed to drugs in utero.

• Sudden Infant Death Syndrome (SIDS): The sudden, unexplained death of an infant, usually during sleep.

• Preterm (Premature) Birth: Birth before 37 weeks of gestation, associated with increased health risks.

• Example: Smoking during pregnancy increases the risk of SIDS and low birth weight.

2.10 Newborn Capabilities

Introduction

Newborns possess a range of reflexes and sensory abilities that help them adapt to life outside the womb.

• Reflexes: Involuntary movements or actions, such as the rooting and sucking reflexes, which are essential for survival.

• Measuring Reflexes: Used to assess neurological development and health.

• Examples of Reflexes: Rooting, sucking, grasping, Moro (startle) reflex.

• Newborn Behaviors: Include crying, sleeping, feeding, and bonding with caregivers.

• Sensory Abilities: Newborns can see, hear, taste, smell, and feel touch, though these senses are not fully developed at birth.

• Example: Newborns prefer their mother's voice and can recognize familiar smells.

Potential Short-Answer Questions Topics

Introduction

Students should be prepared to explain key concepts, provide examples, and connect terms to real-world situations.

• Nature vs. Nurture: How do heredity and environment work together in development?

• Behavioral Genetics: What do twin and adoption studies show about human development?

• Prenatal Testing: What are the purposes and differences between prenatal tests?

• Prenatal Development: What are the key terms and changes in the germinal, embryonic, and fetal stages?

• Teratogens and Health Risks: What are teratogens and how do they affect development?

• Newborn Capabilities: What are examples of newborn reflexes and their purposes?

Table: Stages of Prenatal Development

Stage	Time Frame	Main Events
Germinal	Conception to 2 weeks	Fertilization, cell division, implantation
Embryonic	3 to 8 weeks	Organogenesis, formation of major structures
Fetal	9 weeks to birth	Growth, maturation of organs, movement