Psychology Chapter 1: Introduction

Development Concepts

• Development begins at conception and continues throughout the lifespan, involving both growth and decline.
• Plasticity refers to the capacity for change in response to environmental influences.
• The study of development is multidisciplinary, integrating insights from psychology, sociology, anthropology, neuroscience, and medicine.

Contextual Influences

• Development is shaped by historical, economic, social, and cultural factors, affecting normative age-graded and history-graded influences.
• Normative age-graded influences include events like puberty or menopause that are typical for specific age groups.
• Nonnormative life events refer to unusual occurrences with significant personal impact, such as personal trauma or unique experiences.

Lifespan Perspective

• Development is lifelong, meaning no single period dominates growth or change.
• It is multidimensional, affecting physical, cognitive, emotional, and social aspects simultaneously.
• Development is multidirectional, involving growth, maintenance, and loss regulation, especially prominent in later adulthood.

Ethnicity, SES, and Gender

• Ethnicity encompasses cultural heritage, nationality, race, religion, and language, influencing identity and experiences.
• Socioeconomic status (SES) groups individuals based on occupational, educational, and economic characteristics, often implying inequality.
• Gender refers to social and cultural characteristics attributed to males and females, impacting development experiences.

Dynamic and Cumulative Nature

• Development involves a dynamic interplay between biology and the environment, fostering reciprocal influences in growth.
• It is cumulative, where prior experiences and development stages affect future growth.

Contemporary Concerns in Development

• Health and well-being related to lifestyle and psychological states are increasingly recognized as influential factors.
• Parenting and education concerns relate to children's development and the role of technology in lives of families.
• Sociocultural contexts shape development patterns concerning health, parenting, and educational practices.

Biological Processes of Development

• Development is marked by biological changes, including physical growth, motor skills, and sensorimotor learning.
• Infants develop motor skills through active engagement, where perception and action are interlinked.
• Environmental factors and parental practices greatly influence motor development and skill acquisition.

Milestones in Infant Development

• Infants' motor skills evolve through stages: head control in weeks, sitting with support by 2 months, independent sitting by 6-7 months, and standing alone by 10-12 months.
• Motor development results from a combination of genetic predisposition and active efforts driven by motivation.### Non-Harmful Procedures and Research Ethics
• Informed consent is essential before conducting any research.
• Confidentiality must be maintained to protect participants' privacy.
• Debriefing provides participants with information about the study after it concludes.
• Eclectic theoretical orientation selects techniques from various theories for optimal outcomes.

Biological Beginnings in Development

• Mitosis involves cellular reproduction resulting in two identical cells.
• Meiosis creates gametes (sperm and eggs), leading to genetic diversity.
• Fertilization occurs when sperm and egg combine to form a zygote.

Genetic Foundations of Development

• Chromosomes are structures composed of DNA, containing genetic information.
• A human has 23 pairs of chromosomes, forming their genotype.
• Phenotype refers to observable traits, influenced by genotype and environmental factors.
• Gene activity can be influenced by environmental elements, affecting traits and development.

Sources of Genetic Variability

• Identical twins originate from a single zygote, resulting in genetically identical individuals.
• Fraternal twins result from two separate fertilized eggs, similar to ordinary siblings.
• Mutated genes can alter DNA segments, potentially leading to diseases.
• Susceptibility genes increase vulnerability to diseases, while longevity genes promote healthy aging.

Genetic Principles in Heredity

• The dominant-recessive principle determines trait expression based on gene dominance.
• Sex-linked genes can lead to conditions such as hemophilia, primarily affecting males.
• Chromosomal disorders like Down syndrome arise from an extra chromosome 21, leading to recognizable physical traits and developmental challenges.

Additional Genetic Disorders

• Klinefelter syndrome affects males with an extra X chromosome, leading to various physical and developmental issues.
• Turner syndrome involves females missing an X chromosome, resulting in short stature and fertility issues.
• Fragile X syndrome is linked to an abnormal X chromosome and can cause intellectual disabilities.

Gene-Linked Abnormalities and Diagnoses

• Phenylketonuria (PKU) prevents proper metabolism of phenylalanine due to a recessive gene.
• Sickle-cell anemia, common in African Americans, causes red blood cells to become misshaped, impairing oxygen transport.

Reproductive Choices and Diagnostic Tests

• Common prenatal diagnostic tests include ultrasound sonography, amniocentesis, and maternal blood screening.
• Infertility, characterized by the inability to conceive after a year of unprotected intercourse, may require medical intervention.

Gene-Environment Interactions

• Environmental influences can dramatically affect gene expression and individual traits, such as reactions to stress.
• Genotype-environment correlations, including passive and evocative correlations, illustrate how genetics and environment shape development.

Prenatal Development Overview

• Prenatal development progresses through distinct stages, susceptible to teratogens that may harm fetal development.
• Adequate prenatal care is crucial for monitoring and supporting healthy fetal growth and preventing complications during birth.### Fetal Period
• Begins at two months after conception, lasting for about 7 months until birth.
• At 20 weeks, the fetus is approximately 12 inches long and weighs close to 1 pound.
• Heartbeat can be heard using an ordinary stethoscope.
• Fetus demonstrates reflexes such as thumb sucking and hiccups.
• Physical features, including hair, eyelashes, and eyebrows, become noticeable.

First Trimester

• Ranges from conception to 4 weeks; the zygote is less than 1/10 inch long.
• Development of spinal cord, nervous system, gastrointestinal system, heart, and lungs.
• By 8 weeks, the fetus grows to just over 1 inch; facial features start to form.
• Significant movements and rudimentary breathing are observed.

Second Trimester

• At 24 weeks, the fetus is about 14 inches long, weighing 1 to 1.5 pounds.
• Skin develops a protective coating (vernix caseosa) and appears wrinkled.
• Eyes open and waste matter begins to accumulate in the bowel.
• The fetus shows strong grip and increased activity.

Third Trimester

• At 28 weeks, approximately 16 inches long and weighs about 3 pounds.
• Neurons in the fetal brain grow at an impressive rate of 250,000 per minute during early pregnancy.
• By 32 weeks, the fetus weighs between 4 to 5 pounds and shows distinct sleep-wake cycles.
• At 36 to 38 weeks, weights range from 6 to 7.5 pounds with skin less wrinkled and thicker vernix caseosa.

Teratology and Prenatal Hazards

• Teratogen: Any agent that can cause birth defects or adversely affect cognitive/behavioral development.
• The impact of teratogens varies based on exposure dosage, genetic susceptibility, and timing of exposure.
• Prescription drugs (like antibiotics and hormones) and certain nonprescription drugs (like high doses of aspirin) can act as teratogens.
• Psychoactive drugs (alcohol, nicotine, caffeine) are associated with significant risks, including fetal alcohol spectrum disorders (FASD) and developmental issues.

Environmental Hazards

• Radiation, toxic waste, and chemical pollutants pose risks to fetal development.
• Maternal diseases such as rubella, syphilis, and diabetes can have detrimental effects.

Maternal and Paternal Factors

• Maternal nutrition, age, and emotional state can influence prenatal development.
• Paternal factors, including age and exposure to harmful substances, also affect the embryo/fetus.

Birth Process

• Comprises three stages: labor, delivery, and afterbirth.
• The first stage involves uterine contractions lasting from 6 to 12 hours.
• The second stage, when the baby moves through the birth canal, lasts approximately 45 minutes to an hour.
• The third stage involves the expulsion of the placenta and umbilical cord.

Assessing the Newborn

• The Apgar scale assesses newborn health based on heart rate, respiratory effort, muscle tone, body color, and reflex irritability at one and five minutes post-birth.

Preterm and Low Birth Weight Infants

• Low birth weight: below 5.5 pounds; very low birth weight: below 3 pounds 4 ounces; extremely low birth weight: under 2 pounds.
• Preterm infants are born before 37 weeks of gestation and may face various health and developmental challenges.

Postpartum Period

• Lasts about 6 weeks, during which the mother's body adjusts back to nearly pre-pregnant state.
• Postpartum blues are common (70%), while postpartum depression affects about 10% of women, requiring treatment options including medication and therapy.

Physical Development in Infancy

• Growth patterns: Cephalocaudal (top down) and proximodistal (center outwards).
• The brain develops rapidly with around 100 billion neurons at birth, necessitating protection from trauma.
• Blooming and pruning of neural connections occur as the brain develops; unused connections are eliminated.

Neuroconstructivist View

• Brain development is influenced by the interaction between biological processes and environmental contexts.