Developmental Psychology: Genetics, Brain, and Early Childhood

What is DNA?

The molecule that carries genetic instructions for all living organisms.

What do chromosomes do?

They store and transmit genetic information through genes.

Define genotype and phenotype.

Genotype = genetic makeup; Phenotype = observable traits.

What process produces gametes?

Meiosis, which halves the number of chromosomes to ensure genetic variation.

Difference between monozygotic and dizygotic twins?

Monozygotic = identical, one zygote splits; Dizygotic = fraternal, two fertilized eggs.

What are dominant and recessive genes?

Dominant alleles express traits even if only one copy is present; recessive alleles need two copies.

Define polygenic inheritance.

Traits influenced by many genes, such as height and intelligence.

What is a mutation?

A sudden change in a DNA segment that may be harmful or beneficial.

Name the three prenatal periods.

1. Germinal (0-2 wks) 2. Embryonic (3-8 wks) 3. Fetal (9 wks-birth).

What happens during the embryonic period?

Formation of major organs and body structures; most sensitive to teratogens.

Define teratogen and give examples.

An environmental agent causing prenatal damage; e.g., alcohol, drugs, infections, radiation.

When is prenatal development most vulnerable?

During the embryonic period (weeks 3-8).

Why is folic acid important in pregnancy?

Prevents neural tube defects and supports brain development.

How does stress affect prenatal development?

Chronic stress raises cortisol, reducing oxygen and nutrients for the fetus.

Preterm vs. Small-for-Date infants?

Preterm = born before 37 weeks; Small-for-Date = full-term but underweight due to growth restriction.

What is kangaroo care?

Skin-to-skin contact promoting weight gain, bonding, and regulation in preterm infants.

Cephalocaudal vs. Proximodistal growth?

Cephalocaudal = head to toe; Proximodistal = center outward.

Define synaptic pruning.

Removal of unused neural connections to improve brain efficiency.

What is myelination?

Formation of fatty sheaths around neurons to speed communication.

What is a sensitive period?

A time when the brain is especially receptive to learning certain skills.

How does experience affect brain development?

Through experience-expectant and experience-dependent growth that shapes neural connections.

Why is sleep important for infants?

Supports brain maturation and learning; newborns sleep ~16-18 hours/day.

Describe the dynamic systems theory of motor development.

Motor skills emerge from interaction between brain, body, goals, and environment.

List major motor milestones.

Rolling (3 mo), sitting (6 mo), crawling (7-9 mo), walking (~12 mo).

How does culture influence motor development?

Cultural practices can accelerate or delay milestones, e.g., early walking in African regions.

What are the benefits of breastfeeding?

Provides nutrition, immunity, bonding, and reduces disease risk.

What are growth trends during infancy?

Rapid growth in the first year; weight triples, height increases by 50%.

Piaget's first stage?

Sensorimotor stage (birth-2 yrs).

What is object permanence?

Understanding that objects exist even when unseen (8-12 months).

What is deferred imitation?

Remembering and copying a behavior after delay, showing memory development.

What is habituation?

Gradual reduction in response to repeated stimulation.

Describe Vygotsky's zone of proximal development.

Range of tasks a child can do with guidance but not alone.

Define scaffolding.

Supportive assistance that helps a child master new skills within the ZPD.

What is the information-processing model?

Mind viewed as a system that processes input through memory and attention mechanisms.

Key early language milestones?

Cooing (2 mo), babbling (6 mo), first words (~1 yr), two-word speech (~2 yrs).

What supports early language learning?

Joint attention, infant-directed speech, and social interaction.

Applied: A baby searches for a hidden toy—what concept is shown?

Object permanence (Piaget).

Erikson's first two stages?

Trust vs. Mistrust; Autonomy vs. Shame/Doubt.

When do self-conscious emotions appear?

Around 18-24 months; requires self-awareness.

Define emotion regulation.

The ability to manage and adjust emotional reactions appropriately.

What is social referencing?

Using caregiver's emotional cues to guide behavior (8-10 mo).

Four attachment types?

Secure, Avoidant, Resistant, Disorganized.

What does Ainsworth's Strange Situation measure?

Attachment quality based on infant reactions to caregiver separation and reunion.

What influences attachment security?

Caregiver sensitivity, consistency, stress, and family context.

Define temperament.

Early-appearing differences in emotional reactivity and regulation.

What is the goodness-of-fit model?

Parenting that matches child temperament for adaptive outcomes.

Applied: A baby cries when mom leaves but is soothed upon return.

Secure attachment.

Applied: A baby avoids eye contact and ignores mom's return.

Avoidant attachment.

Applied: A baby resists comfort when reunited with mom.

Resistant (ambivalent) attachment.

Applied: A baby shows confused, contradictory behavior.

Disorganized attachment.

What are Thomas & Chess's temperament types?

Secure, Difficult, Slow-to-warm-up, Unclassified.

Individualistic vs. Collectivistic cultures?

Individualistic = independence; Collectivistic = group harmony and interdependence.

What is Bronfenbrenner's ecological systems theory?

Development occurs in nested systems: micro, meso, exo, macro, and chrono.

How does socioeconomic status (SES) affect development?

Impacts access to resources, parenting styles, and opportunities.

Define correlation vs. causation.

Correlation = relationship; Causation = direct effect proven through experiment.

What is a longitudinal design?

Same participants studied repeatedly over time to track change.

What is a cross-sectional design?

Different age groups studied at one point in time.

Define reliability and validity in research.

Reliability = consistency; Validity = accuracy of measurement.

What does 'nature vs. nurture' refer to?

Interaction between genetic inheritance and environment in shaping behavior.

What is a sensitive period in development?

Time when experiences have maximal impact on brain development.

Applied: A child's behavior improves when parents attend parenting classes—what system is this?

Exosystem influence (Bronfenbrenner).

Human chromosomes have ___ pairs

23

____ duplicates itself through mitosis

DNA

Temperament is the ability to control a dominant response in order to plan and execute a more adaptive response

False