Developmental Psychology: Key Concepts and Research Methods

Lifelong development

Growth and change occur from conception through old age, not just in childhood.

Multidimensional development

Development includes biological, cognitive, and socioemotional changes.

Multidirectional development

Abilities may improve in some areas while declining in others (e.g., older adults gain vocabulary but lose reaction time).

Plastic development

People can change and adapt; skills can be improved with experience.

Influenced by multiple contexts

Family, culture, SES, and historical events all shape development.

Cross-sectional research design

Compares different age groups at one time (quick, but cohort effects).

Longitudinal research design

Follows the same people over time (shows true change, but time-consuming).

Sequential research design

Combines cross-sectional and longitudinal (separates age vs. cohort effects, but still costly).

Piaget's main idea

Children actively construct knowledge through stages of cognitive growth.

Criticism of Piaget's theory

Underestimates children, doesn't account for culture.

Freud's main idea

Personality develops through psychosexual stages.

Criticism of Freud's theory

Too focused on sex, not scientific, limited sample.

Skinner's main idea

Behavior is shaped by reinforcement and punishment (operant conditioning).

Criticism of Skinner's radical behaviorism

Ignores mental processes and biology.

Bronfenbrenner's bioecological theory

Development is shaped by multiple systems (micro, meso, exo, macro, chrono).

Criticism of Bronfenbrenner's theory

Too broad and descriptive, difficult to test.

Vygotsky's main idea

Learning happens through social interaction and cultural tools.

Scaffolding in Vygotsky's theory

Temporary support from adults that helps a child master tasks.

Strength of observational research

Captures real behavior.

Weakness of observational research

Little control.

Strength of self-reports

Access to thoughts/feelings.

Weakness of self-reports

Bias, inaccuracy.

Strength of physiological measures

Objective data.

Weakness of physiological measures

Costly, can't show cause.

Germinal period (0-2 weeks)

Fertilization, zygote forms, cell division, implantation.

Embryonic period (3-8 weeks)

Major organs form, heart beats, most vulnerable to teratogens.

Fetal period (9 weeks-birth)

Growth, brain development, movement, age of viability ~22-24 weeks.

Maternal ages as risk factors

Under 16 and over 35 → higher miscarriage and complications.

Maternal stress effects on prenatal development

Stress hormones affect fetus → low birthweight, prematurity.

Factors influencing teratogen effects

Timing, dosage, genetic vulnerability, multiple risks.

Example teratogen: Alcohol

Fetal Alcohol Syndrome: facial abnormalities, cognitive delays.

Example teratogen: Smoking

Low birthweight, prematurity, breathing issues.

Example teratogen: Rubella

Blindness, deafness, heart defects if early in pregnancy.

Example teratogen: Lead

Low birthweight, intellectual disability, attention problems.

Stages of labor

1) Dilation/effacement of cervix, 2) Delivery of baby, 3) Placenta expelled.

Birthing options besides hospital

Home birth or birthing center (less medical intervention, but riskier).

When is a C-section necessary?

Breech position, fetal distress, multiple births, prolonged labor.

APGAR test measures

Appearance, Pulse, Grimace, Activity, Respiration.

APGAR scoring system

7-10 = healthy, 4-6 = needs help, 0-3 = critical condition.

Strongest newborn senses at birth

Hearing and smell.

Weakest sense at birth

Vision (blurry, improves over months).

Risks of low birthweight

Breathing problems, difficulty feeding, later developmental delays.

Weight change in the first year

Doubles by 5 months, triples by 12 months.

Synaptogenesis

Rapid creation of neural connections in infancy.

Synaptic pruning

Removal of unused neural connections.

Myelination

Fatty coating of axons that speeds neural signals.

Typical motor milestone: Rolling over

~3 months.

Sitting without support

~6 months.

Crawling

~8-9 months.

Walking independently

~12 months.

Running

~18 months.

Experience-expectant brain development

Universal experiences needed for typical development (e.g., vision, language exposure).

Experience-dependent brain development

Growth from unique experiences (e.g., playing piano).

Infant vision at birth

8-12 inches clear, color vision by 4 months, depth perception by ~6-8 months.

Habituation

Decreased response to repeated stimulus (shows memory).

Classical conditioning in infants

Learning to associate two stimuli (e.g., bottle = feeding).

Operant conditioning in infants

Behavior shaped by reinforcement (smiling → gets attention).

SIDS reduction

Sleep on back, firm mattress, no soft bedding, no smoking.

Marasmus

Severe calorie deficiency → wasting away.

Kwashiorkor

Protein deficiency → swollen belly, immune issues.

Sensorimotor Stage 1 (0-1 month)

Reflexes (sucking, grasping).

Sensorimotor Stage 2 (1-4 months)

Primary circular reactions (repeated actions focused on body).

Sensorimotor Stage 3 (4-8 months)

Secondary circular reactions (repeated actions on environment).

Sensorimotor Stage 4 (8-12 months)

Coordination of secondary reactions (goal-directed, object permanence begins).

Sensorimotor Stage 5 (12-18 months)

Tertiary circular reactions (trial and error exploration).

Sensorimotor Stage 6 (18-24 months)

Mental representation, symbolic play, deferred imitation.

Cooing

~2 months.

Babbling

~6 months.

First words

~12 months.

Two-word combinations

~18-24 months.

Phonological development

Learning sounds of language.

Semantic development

Learning word meanings.

Syntactic development

Learning grammar rules.

Pragmatic development

Learning how language is used socially.

Social smiling

~6 weeks.

Laughter

~3-4 months.

Anger

~4-6 months.

Fear/stranger wariness

Begins ~6 months, peaks ~12 months, declines after ~2 years.

Self-soothing in infants

Behaviors like thumb-sucking or rocking to calm.

Self-soothing in toddlers

Using words, moving away, or comfort objects.

Importance of attachment bonds

Provide security, regulate stress, encourage exploration.

Characteristics of secure attachment

Distressed at separation, comforted at reunion, uses caregiver as base.

Characteristics of avoidant attachment

Ignores caregiver, little distress at separation, avoids reunion.

Characteristics of resistant (ambivalent) attachment

Clingy, distressed when caregiver leaves, angry at reunion.

Characteristics of disorganized attachment

Contradictory or confused behavior, linked to neglect/trauma.

Easy temperament

Regular routines, adaptable, generally positive mood.

Difficult temperament

Irregular routines, intense reactions, not adaptable.

Slow-to-warm-up temperament

Low activity, negative mood, adapts slowly.

Social referencing

Infant looks at parent's face to decide whether to approach a stranger.

Marshmallow test

Self-control (delayed gratification).

Secure attachment outcomes

Predicts better emotion regulation, problem-solving, and social skills.