Understanding Child Development

Introduction to Child Development

• Understanding child development helps parents and caregivers make informed decisions, such as dealing with children's anger with sympathy or time-outs rather than spanking.
• Empathy, the ability to understand and share the feelings of others, is crucial for those working with children.
• Understanding child development can inform social policies like understanding effects of violent media or improving education.
• Examining human nature through the lens of child development helps answer deep questions about how early experiences shape long-term development.
  • The Romanian Adoption Study illustrates the effects of early institutionalization and the importance of timely positive interventions.

Philosophical Issues in Child Development

• Plato (4th century B.C.) believed children are born with innate knowledge and emphasized self-control and discipline in child-rearing; certain knowledge is hardwired from birth.
• Aristotle (4th century B.C.) thought discipline necessary but education and child-rearing should be tailored to each child's needs. Knowledge comes from experience, and children are born as "blank slates."
• John Locke (17th century) saw a child's mind as a blank slate shaped by experience, advocating strict discipline early followed by more freedom.
• Jean-Jacques Rousseau (18th century) argued children are inherently good and should have freedom from birth, learning best through interactions, and formal education should be delayed to around age 12.
• Charles Darwin (19th century) theory of evolution prompted studying child development to understand human nature. Variation, natural selection, and inheritance influenced the scientific study.
• Philosophical issues remain central in modern research, now using scientific methods rather than relying on observations alone to explore innate knowledge.
  • Nativists believe evolution gives infants specialized abilities.
  • Empiricists state that children learn through experience and general learning mechanisms.

Enduring Themes in Child Development

• Seven core themes are central: nature and nurture, the active child, continuity and discontinuity, mechanisms of change, sociocultural context, individual differences, and research and children's welfare.
• Development comes from the interplay between genetics and environmental influences.
  • Nature is our biological endowment (genes).
  • Nurture is the physical and social environments that influence development.
• Genome: a person's complete set of hereditary information, influences behaviors and experiences.
  • Experiences and behaviors can also influence the genome, which includes proteins regulating gene expression.
  • Epigenetics is the study of stable changes in gene expression mediated by the environment.
    • Methylation - a biochemical process that suppresses gene activity and expression.
• Active Child: Children actively shape their development through their actions, like focusing on objects or through play, which aids language learning.
• Continuity and Discontinuity: Development may be gradual (continuous) or occur in distinct stages (discontinuous).
  • Continuous development: Changes with age occur gradually in small increments.
  • Discontinuous development: Changes with age include occasional large shifts; stage theories propose development occurs in distinct age-related stages.
• Mechanisms of Change: Cognitive development arises from various mechanisms such as effortful/focusing attention, experience, external factors, genetics, and brain processes.
  • Effortful attention involves voluntary control of one's emotions and thoughts.
  • Variations in genes are associated with variations in the quality of performance requiring effortful attention.
  • Focused attention example is concentrating on homework amid distractions.
• Role of Sleep: Essential for learning and healthy development.
• Sociocultural Context: Environment, including cultural, social, and economic factors, shapes development.
  • Includes the people with whom they interact (immediate factors) and characteristics of the broader society (cultural practices).
  • Socioeconomic status (SES) as a measure of social class based on income and education.
  • Cumulative risk is the accumulation of disadvantages over years of development.
• Individual Differences: Why and how children develop differently is a major question, considering factors like activity levels, temperament, intelligence, persistence, and emotionality.
  • Scarr: Genetics, treatment of children by parents and others, reactions to similar experiences, and choice of environments can lead to differences.
• Research and Children's Welfare: Research in child development contributes to improving children's lives, especially in education or legal contexts like early intervention programs or addressing childhood trauma.

Methods for Studying Child Development

• Scientific Method: Approach to testing beliefs via choosing a question, formulating a hypothesis, testing the hypothesis, and drawing a conclusion.
• Hypotheses are testable predictions about phenomena or relations.
• Reliability: Consistency of independent measurements of behavior.
  • Interrater reliability: Agreement in observations by different raters.
  • Test-retest reliability: Similarity of a participant's performance on two or more occasions.
• Validity: The degree to which a test measures what it intends to measure.
• Internal validity: degree to which effects observed within experiments can be attributed to the tested factor.
• External validity: The degree to which research results can generalize beyond the study's particulars.
• Naturalistic Observation: Observing behavior in natural settings.
  • Strength: High ecological validity.
  • Limitation: Lack of control over external variables.
• Structured Observation: Controlled settings to elicit specific behaviors.
  • Strength: Allows researchers to manipulate variables.
• Self-Reports: Surveys, interviews, or questionnaires.
  • Structured interview: All participants are asked the same questions.
  • Clinical interview: Questions are adjusted in accord with the interviewee's answers.
• Correlation vs. Causation:
  • Correlation: Examines the relationship between variables.
  • Causation: Requires experimental designs to test how one variable influences another.
  • Direction-of-causation problem: Correlation between two variables does not indicate which, if either, variable causes the other.
  • Third-variable problem: A correlation may stem from both variables being influenced by a third variable.
• Research Designs:
  • Cross-Sectional Studies: Compare different age groups at one time.
  • Longitudinal Studies: Follow the same group over time to track changes.
  • Microgenetic Designs: Study the same participants repeatedly over a short period.
• Ethical Considerations: Researchers must maximize benefits, minimize harm, respect dignity, ensure equity, and maintain scientific integrity.

Prenatal Development Hazards

• Miscarriage (Spontaneous Abortion): Around 15% of clinically recognized pregnancies end in miscarriage, caused by genetic abnormalities or environmental influences.
• Recurrent miscarriages (three or more consecutive) affect about 1% of pregnant individuals.
• Teratogens (Environmental Agents That Harm Development): External agents that cause birth defects, developmental delays, or death in a fetus.
  • Sensitive periods are during early prenatal development (embryonic stage, weeks 3-9).
  • Dose-Response Relation: Higher exposure leads to greater damage, with multiple risk factors having cumulative effects.

Teratogens and Their Effects

• Alcohol: Leading cause of fetal brain injury, causing Fetal Alcohol Spectrum Disorder (FASD).
  • Results in characteristic facial features, intellectual disabilities, ADHD, learning difficulties.
• Nicotine: Reduces oxygen supply to the fetus and increases risk of low birth weight, sudden infant death syndrome (SIDS), ADHD, and respiratory problems.
• Opioids: Can cause Neonatal Abstinence Syndrome (NAS) with symptoms like tremors, seizures, feeding difficulties, and breathing problems.
• Marijuana: Increases risk of attention, memory, and impulsivity issues and is often used with tobacco, making it difficult to isolate its effects.
• Environmental Pollutants: Toxic metals, pesticides, plastic chemicals, and air pollution can cross the placenta to harm fetal development.
• Lead exposure is linked to low birth weight, preterm birth, and neurodevelopmental issues.
• PCBs are linked to smaller head size and cognitive deficits.
• Maternal Factors -Age: Teen pregnancies have a higher risk of infant mortality, while older pregnancies have an increased risk of genetic abnormalities and complications. -Nutrition: Folic acid deficiency can cause neural tube defects. Poor nutrition is linked to long-term obesity risk. -Maternal Stress: High cortisol levels can affect fetal development, linked to low birth weight, emotional difficulties, and ADHD.

Birth Experience

• Stages of Labor and Birth: -Stage 1: Uterine contractions begin and dilate the cervix (can last 12-18 hours for first-time births). -Stage 2: Baby moves through the birth canal. Squeezing stimulates breathing hormones and removes fluid. -Stage 3: The placenta is expelled from the uterus.
• Cultural Variations in Birth Practices:
  • Medicalized births in Western countries involve hospitals, pain relief, and C-sections.
  • Traditional societies favor home births with midwives, natural pain management, and social support.
  • Cultural beliefs influence pain perceptions, support, and rituals.
• The Newborn Infant: -State of Arousal: Newborns cycle through six sleep-wake states, with active sleep (REM) crucial for brain development and quiet sleep for growth. -Crying peaks around 6 weeks and then declines. -Infant Mortality: Higher in low-income populations due to healthcare disparities; the U.S. has higher rates than other wealthy countries. -Low Birth Weight: Defined as less than 5.5 pounds, caused by preterm birth, maternal smoking, malnutrition, stress. -Treatment: Kangaroo care (skin-to-skin contact) regulates body temperature, breathing, and bonding.

Genetic Foundations of Development

• Genotype: The genetic material inherited from parents.
• Phenotype: The observable characteristics influenced by genes and the environment.
• Environment: Includes every aspect of an individual's surroundings, influencing gene expression.
• Genome: The complete set of DNA of any organism including all its genes.
• Chromosomes: 46 total (23 pairs), half from each parent.
• DNA (deoxyribonucleic acid): Contains genetic instructions.
• Genes: Segments of DNA that regulate development, sections of chromosomes that are the basic unit of heredity in all living things.
• Crossing over: Sections of DNA switch from chromosome to the other, promoting variability among individuals.
• XX = Female, XY = Male (father's sperm determines sex).
• Endophenotypes: Intermediate phenotypes (brain, nervous systems) that do not involve overt behavior.
• Regulator genes: Control the activation and deactivation of other genes.
• Epigenetics: Environmental factors influence whether genes are "on" or "off" without altering DNA.
• Patterns of Inheritance: -Alleles are two or more different forms of a gene (same trait or characteristic). -Dominant-recessive patterns: Dominant allele overrides recessive; recessive only expresses if inherited from both parents. -Homozygous: Having two of the same allele for a trait. -Heterozygous: Having two different alleles for a trait. -Carriers: Individuals with one dominant and one recessive gene for a trait. -Polygenic inheritance: Most traits are influenced by multiple genes.
• Sex-linked inheritance: Traits carried on the X chromosome are more likely to affect males and are called Color blindness, hemophilia.
• Chromosomal Abnormalities: Errors in meiosis cause genetic disorders (Down syndrome is an extra chromosome 21).
• Phenylketonuria (PKU): A disorder by a defective recessive gene on chromosome 12 that prevents metabolizing phenylalanine.

Mutations and Genetic Variability

• Mutations: Random DNA changes that can be beneficial, neutral, or harmful.
• Genetic diversity: Enhanced through mutations, genetic recombination, and meiosis.
• Behavioral Genetics: The variation in behavior results from the combination of genetic and environmental factors.
• Heritable: Characteristics or traits that are genetically transmitted.
• Twin and Adoption Studies: -Goal: Determine the relative influence of genes vs. environment on traits. -Monozygotic (Identical) Twins: share 100% of genes. -Dizygotic (Fraternal) Twins: Share 50% of genes (like regular siblings). -Adoption Studies: Comparing children with biological vs. adoptive parents to separate genetic and environmental influences.
• Heritability: -Definition: Statistical estimate of variance on a trait attributable to genetic differences (expressed as a value between 0 and 1). -Misconceptions: Does not apply to individuals (only populations); high heritability doesn't mean "genetically determined" (environment still matters) and changes depending on context.

Molecular Genetics Research Designs

• Explores how specific genes influence behavior and development.
• Goes beyond traditional twin/adoption studies by identifying actual genes associated with traits.
• Methods: -Genome-Wide Association Studies (GWAS): identifies genetic variations linked to traits or disorders. -Genome-Wide Complex Trait Analysis (GCTA): A statistical method to estimate heritability at the molecular level. -Polygenic Scores: Summarizes the combined influence of multiple genes on a trait

Development of the Brain

• Basic Brain Structures:
  • Neurons: Specialized cells for sending and receiving messages.
  • Cell body: Contains the basic biological material.
  • Dendrites: Receive signals from other cells.
  • Axons: Transmit signals away from the cell body.
  • Synapses: Connections where signals pass between neurons.
  • Glial cells: Support neurons and produce myelin.
  • Myelin sheath: Fatty sheath that increases the speed and efficiency of information transmission.
• Cerebral Cortex: The "gray matter" of the brain, with four lobes.
  • Occipital lobe: Processes visual information.
  • Temporal lobe: Associated with speech, language, music, and emotional information.
  • Parietal lobe: Associated with spatial processing and sensory information integration.
  • Frontal lobe: Associated with working memory and cognitive control.
  • Association areas: Lie between major sensory and motor areas and process and integrate input.
• Cerebral Hemispheres: the two halves of the cortex.
• Corpus Callosum: A dense tract of nerve fibers that enables communication between the hemispheres.
• Cerebral Lateralization: Specialization of the hemispheres for different modes of processing.

Key Processes in Brain Development

• Neurogenesis: Formation of neurons (mostly completed before birth).
• Arborization: Formation of new dendritic trees and branches.
• Spines: Formations on dendrites that increase the dendrites' capacity to form connections.
• Myelination: Formation of myelin (fatty sheath) around axons to speed/increase information processing.
• Synaptogenesis: Neurons form synapses, resulting in trillions of connections.
• Synaptic Pruning: Synapses that are rarely activated are eliminated.
• Experience:
  • Plasticity: The brain's capacity to be affected by experience.
  • Experience-Expectant Plasticity: Normal wiring occurs as a result of typical experiences.
  • Experience-Dependent Plasticity: Neural connections are created and reorganized throughout life based on individual experiences.
  • Brain Damage and Recovery: Young brains recover better due to higher plasticity.
• Physical Growth and Development:
  • Cephalocaudal Growth: Development proceeds from head to toe.
  • Proximodistal Growth: Development starts from the center of the body outward.

Secular Trends and Breastfeeding

• Secular Trends: Generational changes in physical development.
• Breastfeeding Benefits: It provides antibodies, reduces risk of infections, allergies, and obesity; associated with higher IQ; decreases the parent's risk of breast and ovarian cancer.
• Development of food preferences: -Infants display similar reflexive facial expressions to basic tastes. -Newborns prefer sweetness; young children demonstrate food neophobia (unwillingness to eat new foods). -Limited access to certain foods makes children overindulge when they can. -Parental use of food to control children is a predictor of obesity risk factors. -Branding strategy: Children select and rate familiar brands more highly.
• Childhood Obesity: It is influenced by genetics, diet, activity, and environment. -Higher rates in low-income families due to limited access to healthy food.
• Vaccination and Disease Prevention: It protects against life-threatening illnesses by delivering weak versions of a disease to the body making it produce antibodies, and misconceptions contribute to preventable outbreaks.

Theories of Cognitive Development and Piaget's Theory

• Why Theories Matter: They provide a framework, raise questions, and guide research.
• Piaget's Theory of Cognitive Development: -Core Ideas: Development occurs through stages driven by assimilation, accommodation, and equilibration. -Assimilation: Translating incoming information into understandable concepts. -Accommodation: People adapt knowledge structures to new experiences. -Equilibration: Balancing assimilation and accommodation to create stable understanding. -Piaget's basic assumptions: -Children are active learners and construct their own knowledge. -Learn important lessons on their own rather than needing instruction. - Intrinsic motivation for learning.

Piaget's and Related Cognitive Development Theory

• Sources of Discontinuity: Distinct stages of cognitive development; stages = qualitative leaps.
• Key Properties of Piaget's Stage Theory: -Qualitative Change: Different ages = fundamentally different ways of thinking. -Broad Applicability: Thinking applies to all aspects of cognitive functioning. -Brief Transitions: Fluctuations occur before transitioning to a new stage. -Invariant Sequence: Progress through stages in the same order w/o any skipping.
• Stages of Cognitive Development:
  • Sensorimotor Stage (0-2 years): Intelligence expressed through sensory and motor abilities; object permanence (A-not-B error). -Preoperational Stage (2-7 years): Symbolic representation develops; inability to perform certain mental operations. -Egocentrism is the difficulty adjusting another’s perspective; centration=focusing on one aspect while ignoring others; lack of conservation. -Concrete Operational Stage (7-12 years): Logical reasoning about concrete objects/events; conservation develops; decentration; limited abstract thinking. -Formal Operational Stage (12+ years): Abstract thinking and systematic scientific reasoning not all individuals reach this stage.
• Criticisms: Underestimates infants’ abilities, stages are too rigid/vague & theory understates the contribution of the social world.
• Information Processing Theories: Focus on mental processes (attention, memory, problem-solving); the cognitive system and mental activities used to solve problems.
• Emphasis = thinking as a process that occurs; task analysis= specifying goals, obstacles/simulations.
• Development = continuous, not stage-based (different rates for different tasks).
• Limited-Capacity Processing System: the mind = computer (limited processing capacity) via learning and maturation.
• Problem Solving: Using strategy/flexibility to attain goal.
• Development of Memory: working memory (actively attending to, maintaining/ long-term); capacity & speed (factual, conceptual, or procedural knowledge).
• Explanation of Memory Development: Types of capacity=basic processes (associating or generalizing) &encoding (memory information).
• Strategies: repeat information (aid memory) to solve problems through focusing on relevant information.
• Development of Problem Solving: It is achieved with the increased knowledge improves integrating understanding.

Overlapping Wave Theory & Core Knowledge Theory

• Overlapping Waves Theory: Emphasizes the variability of thinking and gradual movement towards using more and more advance strategies.
• Planning: Problem solving = successful with the need to inhibit the desire to solve the problem immediately
• Core-Knowledge Theories: View children as innate knowing in domains of special evolutionary importance & domain-specific learning.
• Children: -Active learners and well-adapted product of evolution. -Enter world equipped not only with general learning abilities but specialized learning mechanisms for quick, effortless information. -Domain-specific: Particular continent area + Nativism of evolutionary important domains.
• Nativism vs. Constructivism:
  • Nativism is the theory that infants have substantial innate knowledge of evolutionarily important domains (ex: 4 core-knowledge systems).
  • Constructivism is the theory that infants build understanding of innate knowledge through experiences.
• sociocultural theories: approaches that emphasize that other people and the surrounding culture contribute greatly to children's development.
• Guided participation= more knowledge & cultural tools which enhance activity to learn with social learners & continuous changes.
• Portray Children's Nature (Vygotsky's Theory): intertwined w/ other people (gain skills), intent on participating in activities that are prevalent in life with gradual continuous changes.

Sociocultural and Dynamic Systems Theories

• Children are social learners who become full participants (social environment, skills, attitudes and values) through the central metaphor.
• Internalization-Of-Thought Process:
  • behavior is in other's control (statements), then private speech in their own control, then internalized. -Human nature from Michael Tomasello: teachers increase insight, teach others (inclination) & attend and learn (inclination to teach), therefore society increases.
• Product of their culture & development-content varies and shape think accordingly.
• Central Issues:
• Idea changes through others & joint attention
• dynamic-systems theory = detailed analyses (infants' actions like crawl/reach and cognitive development.
• Constant change (thought and action change) integrated system and interaction.

The Core-Knowledge Theory Vygotsky +

• Emphasize innate motivation but the precise analyses, early components (social cultural) and environmental actions.
• Central development issues - how the changes & organizational processes (soft assembly and change every moment).
• Biological: -active roles (biology merges w/ environ) and trying things to change, depending of best fit & behavior patterns as well as self organization.

Social Behavior Psych & Development

• Psychoanalytic Theory = unconscious drives that influence behaviour
• Freud's Development theory = universal, sensitive "erogenous" spots affecting entire lifestyle (id, sexual & pleasure principles!)
• Erickson' theory is similar with additional environment affects that characterize crises they individual must resolve.
• learning = emphasize continuity, welfare + mechanisms
• Watson= study environment rather than thoughts (fear conditioning by association & unethical).
• skinner= intermitted reinfocement (like timeout) & modification patterns (adaptive)
• bandurn = observation & imitation of social