Child Development

meta-analysis

a method for combining the results from independent studies to reach conclusions based on all of them

prefrontal cortex

cortical region associated with planning, reasoning, problem solving, and other high-level mental functions

amygdala

an area of the brain that is involved in emotional reactions

nature

our biological endowment; the genes we receive from our parents

nurture

the environments, both physical and social, that influence our development

genome

each person’s complete set of hereditary information

epigenetics

The study of stable changes in gene expression that are mediated by the environment

methylation

a biochemical process that influences behavior by suppressing gene activity and expression

continuous development

the idea that changes with age occur gradually, in small increments, like that of a pine tree growing taller and taller

discontinuous development

the idea that changes with age include occasional large shifts, like the transition from caterpillar to cocoon to butterfly

stage theories

approaches proposing that development involves a series of large, discontinuous, age-related phases

cognitive development

the development of thinking and reasoning

neurotransmitters

chemicals involved in communication among brain cells

sociocultural context

the physical, social, cultural, political, economic, and historical circumstances that make up any child’s development

socioeconomic status

a measure of social class based on income and education

cumulative risk

the accumulation of disadvantages over years of development

reliability

the degree to which independent measurements of a given behavior are consistent

interrater reliability

the amount of agreement in the observations of different raters who witness the same behavior

test-retest reliability

the degree of similarity of a participant’s performance on two or more occasions

validity

the degree to which a test measures what it is intended to measure

internal validity

the degree to which effects observed within experiments can be attributed to the factor that the researcher is testing

external validity

the degree to which results can be generalized beyond the particulars of the research

epigenesis

the emergence of new structures and functions in the course of development

gametes

reproductive cells that contain only half the genetic material of all other cells in the body

meiosis

cell division that produces gametes

conception

the union of an egg and a sperm

zygote

a fertilized egg cell

embryo

the developing organism from the 3rd to 8th week of prenatal development

fetus

the developing organism from the 9th week to birth

mitosis

cell division that results in two identical cells

embryonic stem cells

embryonic cells, which can develop into any type of body cell

apoptosis

genetically programmed cell death

monozygotic twins

twins that result from the splitting in half of the zygote, resulting in each of the two resulting zygotes having exactly the same set of genes

dizygotic twins

twins that result when two eggs happen to be released into the fallopian tube at the same time and are fertilized by two different sperm; fraternal twins have only half their genes in common

ectopic pregnancy

pregnancy in which the fertilized egg implants and grows in an organ outside of the uterus, preventing normal growth of fetus and putting the expectant parent at risk of life-threatening injury

neural tube

a groove formed in the top layer of differentiated cells in the embryo that eventually become the brain and spinal cord

amniotic sac

a transparent, fluid-filled membrane that surrounds and protects the fetus

placenta

a support organ for the fetus; it keeps the circulatory systems of the fetus and pregnant parent separate, but a semipermeable membrane permits the exchange of some materials between them

umbilical cord

a tube containing the blood vessels connecting the fetus and placenta

cephalocaudal development

the pattern of growth in which areas near the head develop earlier than areas farther from the head

phylogenetic continuity

humans share many characteristics, behaviors, and developmental processes with nonhuman animals, especially mammals, due to our common evolutionary history

habituation

a simple form of learning that involves a decrease in response to repeated or continued stimulation

dishabituation

the introduction of a new stimulus rekindles interest following habituation to a repeated stimulus

teratogen

An external agent that can cause damage or death during prenatal development

sensitive period

The period during which a developing organism is most sensitive to the effects of external factors

dose-response relation

A relation in which the effect of exposure to an element increases with the extent of exposure

sudden infant death syndrome

The sudden, unexpected death of an infant younger than 1 year that has no identifiable cause

fetal alcohol spectrum disorder

The harmful effects of alcohol consumption on a developing fetus, including characteristic facial features, intellectual developmental disorder, attentional challenges, and hyperactivity

state

Level of arousal and engagement in the environment, ranging from deep sleep to intense activity

rapid eye movement sleep

An active sleep state characterized by quick, jerky eye movements under closed lids and associated with dreaming in adults

non-REM sleep

A quiet or deep sleep state characterized by the absence of motor activity or eye movements and more regular, slow brain waves, breathing, and heart rate

swaddling

A soothing technique, used in many cultures, that involves wrapping a baby tightly in cloths or a blanket

colic

Excessive, inconsolable crying by a young infant for no apparent reason

Apgar score

Method for evaluating the health of the newborn immediately following birth based on skin tone, pulse rate, facial response, arm and leg activity, and breathing

infant mortality

Death during the first year after birth

low birth weight

A birth weight of less than 5½ pounds

premature

Any child born at 35 weeks after conception or earlier

small for gestational age

Babies who weigh substantially less than is normal for whatever their gestational age

developmental resilience

Successful development in spite of multiple and seemingly overwhelming developmental hazards

genome

the complete set of DNA of any organism, including all of its genes

genotype

the genetic material an individual inherits

phenotype

the observable expression of the genotype, including both body characteristics and behavior

environment

every aspect of individuals and their surrounding other than genes

chromosomes

molecules of DNA that transmit genetic information; chromosomes are made up of DNA

deoxyribonucleic acid

DNA; Molecules that carry all the biochemical instructions involved in the formation and functioning of an organism

genes

sections of chromosomes that are the basic unit of heredity in all living things

crossing over

the process by which sections of DNA switch from one chromosome to the other; crossing over promotes variability among individuals

mutation

a change in a section of DNA

sex chromosomes

the chromosomes that typically correlate to an individuals assigned sex at birth

endophenotypes

intermediate phenotypes that do not involve overt behavior

regulator genes

genes that control the activity of other genes

alleles

two or more different forms of a gene

dominant allele

the allele that, if present, gets expressed

recessive allele

the allele that is not expressed if a dominant allele is present

homozygous

having two of the same allele for a trait

heterozygous

having two different alleles for a trait

polygenic inheritance

inheritance pattern in which traits are governed by more than one gene

phenylketonuria

a disorder related to a defective recessive gene on chromosome 12 that prevents metabolism of amino acid phenylalanine

carrier genetic testing

genetic testing used to determine whether prospective parents are carriers of specific disorders

prenatal testing

genetic testing used to assess the fetus’s risk for congenital abnormalities

newborn screening

tests used to screen newborn infants for a range of genetic and non-genetic disorders

behavior genetics

the science concerned with how variation in behavior and development results from the combination of genetic and environmental factors

heritable

refers to characteristics or traits that are genetically transmitted

heritability

a statistical estimate of the proportion of the measured variance on a trait among individuals in a given population that is attributable to genetic differences among those individuals

neurons

cells that are specialized for sending and receiving messages between the brain and all parts of the body, as well as within the brain itself

cell body

a component of the neuron that contains the basic biological material that keeps the neuron functioning

dendrites

neural fibers that receive input from other cells and conduct it toward the cell body in the form of electrical impulses

axons

neural fibers that conduct electrical signals away from the cell body to connections with other neurons

synapses

microscopic junctions between the axon terminal of one neuron and the dendritic branches or cell body of another

glial cells

cells in the brain that provide a variety of critical supportive functions

myelin sheath

a fatty sheath that forms around certain axons in the body and increases the speed and efficiency of information transmission

cerebral cortex

the gray matter of the brain, consisting of four distinct lobes

occipital lobe

major area of the cortex that is primarily involved in processing visual information

temporal lobe

major area of the cortex that is associated with speech and language, music, and emotional information

parietal lobe

major area of the cortex that is associated with spatial processing and sensory information integration

frontal lobe

major area of the cortex that is associated with working memory and cognitive control

association areas

parts of the brain that lie between the major sensory and motor areas and that process and integrate input from those areas

cerebral hemispheres

the two halves of the cortex

corpus callosum

a dense tract of nerve fibers that enable the two hemispheres of the brain to communicate

cerebral lateralization

the specialization of the hemispheres of the brain for different modes of processing