AP Psychology 3.1-3.2: Themes and Physical Development

Developmental psychology

The scientific study of how and why human thinking, emotions, behavior, and abilities change across the lifespan. It includes physical, cognitive, and social-emotional development from the prenatal period through old age.

Why is developmental psychology considered a lifespan field?

Although it originally focused mainly on infants and children, it now examines adolescence, adulthood, aging, and transitions throughout the entire human life.

What are the three major dimensions of human development studied by developmental psychologists?

They are physical development, cognitive development, and social-emotional development.

Nature versus nurture

The debate over whether development is primarily influenced by inherited biological factors or by experience and environment. Contemporary developmental psychology generally emphasizes their interaction rather than treating them as independent causes.

How does developmental psychology address nature and nurture?

It examines how biological characteristics and environmental influences jointly shape development. Researchers also study interactions among personal traits, behavior, social settings, and physical environments.

How do personal characteristics and environmental factors interact in development?

A person's biological and psychological characteristics influence behavior, while behavior can alter the surrounding environment. Social relationships, cultural settings, and built environments can then reinforce or redirect development.

Biological essentialism versus neuroplasticity

Biological essentialism emphasizes fixed biological properties, whereas neuroplasticity emphasizes the nervous system's capacity to change in response to experience, learning, and environmental conditions.

Continuity versus discontinuity

A developmental debate about whether change occurs gradually and continuously or through distinct qualitative stages. Stage theories emphasize discontinuity, whereas dynamic and learning-based approaches often emphasize gradual change.

Stability versus change

The question of whether characteristics such as personality, abilities, and behavior remain consistent or are transformed over time. Developmental research investigates both enduring traits and meaningful change.

What is a developmental research method?

A systematic way of studying psychological changes across age or time. Developmental psychologists use methods such as observation, interviews, surveys, and standardized assessments to measure physical, cognitive, and social-emotional development.

What is a longitudinal study?

A study that follows the same participants and measures them repeatedly over an extended period. It can reveal individual developmental trajectories and changes within the same people.

What is a cross-sectional study?

A study that compares people of different ages at one point in time. It is usually faster than a longitudinal study but cannot clearly distinguish age effects from generational or cohort effects.

Longitudinal versus cross-sectional research

Longitudinal research repeatedly studies the same individuals, providing evidence about change within individuals but requiring more time and risking participant attrition. Cross-sectional research compares different age groups at one time, making it efficient but vulnerable to cohort effects.

What is a cohort effect?

A difference between age groups caused by the historical, cultural, or environmental experiences shared by a generation rather than by age-related development itself.

What is a sequential research design?

A design that combines longitudinal and cross-sectional approaches by following multiple age cohorts over time. It helps researchers separate age-related change from cohort and historical effects.

Why are observations especially useful in developmental psychology?

Observing behavior in naturalistic or structured settings allows researchers to study development directly, including behavior that young children may be unable to describe verbally.

What are the major prenatal stages of development?

The germinal stage extends from conception through implantation, the embryonic stage extends from implantation through about the eighth week, and the fetal stage extends from about the ninth week until birth.

What occurs during the embryonic period?

The developing organism's major organs and body structures begin to form. Because organ systems are developing rapidly, this period is especially sensitive to harmful environmental influences.

What occurs during the fetal period?

The developing organism grows substantially, and existing organs and body systems mature and become increasingly functional until birth.

What are teratogens?

Teratogens are environmental agents that can harm prenatal development. Examples include certain drugs, alcohol, toxins, infections, malnutrition, and radiation.

What factors influence the effects of a prenatal teratogen?

Effects depend on factors such as the timing and duration of exposure, the amount of exposure, the specific agent, and genetic characteristics of the developing organism and parent.

Fetal alcohol spectrum disorders

A range of physical, cognitive, and behavioral problems associated with prenatal alcohol exposure. Severe cases may include fetal alcohol syndrome, characterized by growth deficits, distinctive facial features, and central nervous system impairment.

What physical abilities are present in newborns?

Newborns possess reflexes that support survival and early interaction, such as rooting, sucking, grasping, and the Moro reflex. These reflexes are automatic responses to particular stimuli.

How does the brain develop during infancy and childhood?

The brain grows rapidly, forming and strengthening neural connections through both biological maturation and experience. Unused connections may be eliminated through synaptic pruning, while frequently used pathways become more efficient.

What is puberty?

Puberty is the period of biological maturation during which hormonal changes produce sexual maturity and the capacity for reproduction. It also brings growth spurts and other primary and secondary sex characteristics.

Primary versus secondary sex characteristics

Primary sex characteristics involve the reproductive organs and reproductive functions. Secondary sex characteristics are physical changes associated with sexual maturity that are not directly required for reproduction, such as body hair and voice changes.

How does physical development change during adulthood and aging?

Physical development generally reaches a peak in early adulthood and later involves gradual changes such as reduced muscle strength, sensory acuity, bone density, reaction speed, and physiological functioning. The timing and extent of these changes vary among individuals.

What is menopause?

Menopause is the natural end of menstrual cycles and reproductive capacity, typically occurring in middle adulthood as ovarian hormone production declines.

What is neuroplasticity across the lifespan?

Neuroplasticity is the nervous system's ability to reorganize and change in response to maturation, learning, experience, injury, and environmental conditions. Plasticity generally remains possible throughout life, although it may vary with age.