PSY 254 Midterm (Textbook Review)

Reliability

The degree to which independent measurements of a behavior under study are consistent

-Includes interrater reliability (degree of agreement in observations amongst raters) and test-retest reliability (degree of similarity of a participant's performance on two or more occasions)

Validity

The degree to which a test or experiment measures what it is intended to measure

-Includes internal validity (degree of confidence concerning whether the effect observed is due to the factor being tested) and external validity (ability to generalize results beyond the particulars of the research in question)

Structure interview

Research method in which all participants are asked to answer the same predetermined questions

-Could be administered orally or through questionnaires

Clinical interview

A procedure in which questions are adjusted in accord with the answers the interviewee provides; allows collection of unique in-depth information about an individual child

Naturalistic observation

An examination of ongoing behavior in an environment not controlled by the researcher; useful for illuminating everyday social interactions

Structured observation

Involves presenting an identical situation to each participant and recording the participant's behavior

*Ex. Mothers bringing their children to a lab room that has attractive and non-attractive toys scattered around the room; mother is instructed to tell the child which toys not to play with and then the child's behavior is observed

*Advantage over naturalistic observation is that you can directly compare different children's behavior in a given situation because they are all encountering identical situations

Variables

Attributes that vary across individuals and situations, such as age, sex, and popularity

Correlational studies

Studies that are intended to indicate how two variables are related to each other

Correlation

The association between two variables

Direction-of-causation problem (of correlational studies)

The concept that a correlation between two variables does not indicate which, if either, variable is the cause of the other; correlation cannot imply causation

Third variable problem (of correlational studies)

The correlation between two variables may actually be the result of some third, unspecified variable (a latent or confounding variable)

Why might a researcher use a correlational study rather than an experimental study?

The influence of many variables of interest - age, sex, race, and social class among them - cannot be studied experimentally because researchers cannot manipulate them

Experimental designs

Group of approaches that allow inferences about causes and effects to be drawn

*Random assignment and experimental control are crucial to experimental designs

*While they are strong in internal validity, they lack in external validity

Independent variable

-The experimental factor that is manipulated; the variable whose effect is being studied.

-It is a variable that stands alone and isn't changed by the other variables you are trying to measure

-Includes the experience that the children in the experimental group receive, and the children in the control group do not receive

Dependent variable

The behavior/response that is hypothesized to be affected by exposure to the independent variable

Cross-sectional design

A research method which compared children of different ages on a given behavior, ability, or characteristic by studying them roughly at the same time - for example, within the same week or month

-This is the most common and easiest way to study changes and continuities with age

-Strength of this approach is that they are useful for revealing similarities and differences between older and younger children

Longitudinal design

A method of study in which the same participants are studied twice or more over a substantial length of time

-Observes changes and continuities in these children's development at regular intervals during that time

Microgenetic design

A method of study in which the same participants are studied repeatedly over a short period

-Specifically designed to provide an in-depth depitch of the processes that produce change in the same children

-The basic idea of this approach is to recruit children who are thought to be on the verge of an important developmental change, heighten their exposure to the type of experience that is believed to produce that change, and then intensively study that change as it is occurring

Ex. Siegler and Jenkins used a microgenetic design to study how young children discover the "counting-on" strategy for adding two small numbers

Fetuses as young as 30 weeks gestation show ________ and ________ to both visual and auditory stimuli, indicating that their central nervous systems are sufficiently developed for learning and short-term memory to occur.

Habituation, dishabituation

EEG

Electroencephalography; Electrical recordings are obtained through the scalp; used to study the time course of neural events and brain/behavior relationships

MEG

Magnetoencephalography; Detects magnetic fields generated by electrical currents in the brain

Unlike EEG, MEG can be used to localize* the origin of the electrical signals within the brain, as well as their time course

fMRI

Uses a powerful electromagnet to detect fluctuations in cerebral blood flow in different areas of the brain

*DTI is a variant of conventional MRI that uses rate of water diffusion to model 3-D spatial location

*Resting-state fMRI measures brain activity in the absence of any external stimuli or tasks

fNIRS (Functional near-infrared spectroscopy)

An optical imaging technique that measures neural activity by detecting metabolic changes that lead to differential absorption of infrared light in brain tissue, via an optical-fiber skull cap or headband

*Because fNIRS is silent, noninvasive, and does not require head stabilization, it is particularly promising for research with infants and young children

Sensation

The processing of basic information from the external world via receptors in the sense organs (eyes, ears, skin, etc.) and brain

Perception

The process of organizing and interpreting sensory information about the objects, events, and spatial layout of the world around us

Preferential-looking technique

A method for studying visual attention in infants that involves showing infants two images simultaneously to see if the infants prefer one over the other (indexed by longer looking)

*If an infant looks longer at one of the two stimuli, the researcher can infer that (a) the baby can discriminate between them, and (b) the infant prefers one over the other

*Modern versions use automatic eye-trackers

How is habituation used to study sensory and perceptual development in infants?

This procedure involves repeatedly presenting an infant with a particular stimulus until the infant habituates (i.e. until their response declines); then a novel stimulus is presented

-If the infant dishabituates (i.e. beings showing interest agina_, the researcher infers that the baby can discriminate between the old and new stimuli

Why is habituation highly adaptive?

Diminished attention to what is familiar enables infants to pay attention to, and learn about, what is new in their environment

Object permanence

A child's ability to know that objects continue to exist even though they can so longer be seen or heard

*The simplest evidence suggesting that young infants continue to represent an object that has vanished from sight is the fact that they will reach for objects in the dark

Violation-of-expectancy

A procedure used to study infant cognition and object knowledge in which infants are shown an event that should evoke surprise or interest if its goes against something that the infant knows

*The basic assumption is that if infants observe an event that is inconsistent with what they know about the world, they will be surprised - or at least interested; Thus, an unexpected event should evoke a greater response (such as looking longer or a change in heart rate) than an unsurprising event

Epigenesis

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

Gametes (germ cells)

Reproductive cells (egg and sperm) that contain only half of the genetic materials of all the other cells in the body

Meiosis

How gametes are formed; a form of cell division in which the egg and sperm receive only one member from each of the 23 chromosome pairs contained in all other cells in the body

Conception

Union of egg and sperm

Zygote

The fertilized egg

*Has a full complement of human genetic material; 23 chromosomes from the mother and 23 chromosomes from the father

Embryo

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

Fetus

The developing organism from the 9th week to birth

What are the four major development processes which underlie the transformation of a zygote into an embryo and then a fetus?

1. Mitosis: cell division that results in two identical cells

2. Cell migration: movement of newly formed cells away from their point of origin

3. Cell differentiation: specialization of undifferentiated embryonic stem cells

4. Apoptosis: genetically programmed cell death

Identical (monozygotic) twins

Result from the splitting in half of the inner cell mass, thus they have exactly the same genetic makeup

Fraternal (dizygotic) twins

Result when exactly two eggs happen to be released from the ovary into the fallopian tube and both are fertilized

Neural tube

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

Amniotic sac

A membrane filled with a clear, watery fluid in which the fetus floats; it operates as a protective buffer for the developing fetus, providing it with a relatively even temperature and cushioning it against jolting

Placenta

A rich network of blood vessels, weighing roughly one pound, that extends into the mother's uterus; it keeps the circulatory systems of the fetus and mother separate, but a semipermeable membrane permits the exchange of some materials between them (oxygen and nutrients from the mother to fetus, carbon dioxide and waste products from the fetus to mother)

Umbilical cord

A tube containing the blood vessels that connect the fetus and placenta

-The amniotic sac is connected to the placenta via the umbilical cord

Cephalocaudal development

The pattern of growth of the fetus in which areas near the head develop earlier than areas farther from the head (e.g., head before body, hands before feet)

How many weeks gestation are the brain and lungs sufficiently developed that the fetus would have a chance of surviving on its own, without medical intervention?

28 weeks

What types of reflexes do fetuses perform in the womb?

Burping reflex; swallowing amniotic fluid; "fetal breathing" (pulling in and then expelling small amounts of amniotic fluid into the lungs)

Phylogenetic continuity

The idea that because of our common evolutionary history, humans share many characteristics, behaviors, and developmental processes with non-human animals, especially mammals

*Ex. Prenatal scent learning plays an important role in many species' early developmental processes

Fairly direct evidence for fetal learning comes from studies of ______.

Habituation

*Ex. Can observe increases/decreases in fetal heart rate in response to different stimuli

Teratogen

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

*The effects of potential teratogens are heavily influenced by timing (whether they are exposed to the fetus during sensitive/critical periods)

*Include drugs, antidepressants, opioids, marijuana, cigarette smoking, alcohol, environmental pollutants, disease, maternal emotional state, age (too young or old) and nutrition (nutrient deficiencies) of the mother

Dose-response relation

The relation in which the greater the fetus's exposure to a potential teratogen, the more likely it is that the fetus will suffer damage and more severe any damage is likely to be

Sudden Infant Death Syndrome (SIDS)

The sudden, unexpected, and unexplained death of an infant younger than 1 year

*The most common SIDS scenario is that an apparently health baby, usually between 2-5 months of age, is put to bed for the night and found dead in the morning

Fetal programming

Refers to the belated emergence of effects of prenatal experience that "program the physiological set points that will govern physiology in adulthood"

Sleeper effects

The impact of a given teratogen may not be apparent for many years

Neonatal Abstinence Syndrome (NAS)

A form of drug withdrawal seen when fetuses exposed to opioids in the womb are born

Fetal alcohol spectrum disorder (FASD)

Comprises a continuum of alcohol-related birth defects caused by maternal drinking

*Babies born to alcoholic women often exhibit extreme negative outcomes, known as fetal alcohol syndrome

*Maternal alcohol use if the leading cause of fetal brain injury and is generally considered to be the most preventable cause

*When a pregnant woman drinks, the alcohol in her blood crosses the placenta into both the fetus's bloodstream and the amniotic fluid

State

A continuum/level of arousal and engagement in the environment, ranging from deep sleep to intense activity

What are the six states that newborns are in within a 24-hour period?

1. Quiet sleep

2. Active sleep

3. Drowing

4. Alert awake

5. Active awake

6. Crying

Rapid eye movement (REM) sleep

An active sleep state associated with dreaming in adults; it is characterized by quick, jerky eye movements under closed lids, a distinctive pattern of brain activity, body movements, and irregular heart rate and breathing

*REM sleep constitutes fully 50% of a newborn's total sleep time; the proportion of REM sleep then declines quite rapidly

*Some researchers believe that infants spend so much time in REM sleep because it helps develop the infant's visual system

*Another way in which REM sleep may be adaptive for neonates is that the natural jerking movements (called myoclonic twitching) that occur exclusively during REM sleep may give infants opportunities to build sensorimotor maps

*Another distinctive feature of sleep in the newborn period is the neonates' slumbering brains do not become disconnected from external stimulation to the same extent that the brains of older individuals so, which allows newborns to learn during sleep

Non-REM sleep

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

Why do infants cry?

To communicate that they want attention from caregivers for many reasons, including illness, pain, and hunger

Swaddling

An effective soothing technique for crying babies which involves wrapping a young baby tightly in clothes or a blanket, thereby restricting limb movement

Colic

Inconsolable crying for no apparent reason during the first few months of life

Apgar score

-A worldwide evaluation tool used by neonatal caregivers to quickly assess the health of newborn infants immediately following birth

-A cumulative score is derived from ratings of skin tone, pulse rate, facial responses (typically grimacing), arm and leg activity, and breathing strength

Infant mortality

Death during the first year after birth

Low Birth Weight (LBW)

Infants who weigh less than 5.5 pounds at birth

*Most are premature

Premature/preterm

A baby that is born at 35 weeks after conception or earlier (as opposed to the normal term of 38 weeks)

Small for gestational age

When a baby may be either preterm or full-term, but they weigh substantially less than is normal for their gestational age, which is based on weeks since conception

Kangaroo care

When caregivers act as incubators to help maintain the infant's skin temperature and promote breastfeeding, and attachment

-Involves holding the baby to the bare chest

-Can be used for premature infants who are hospitalized

Isolettes

Incubator with controlled environment in which preterm babies are kept in the NICU

Multiple-risk model

A negative developmental outcomes - whether in terms of prenatal or later development - more likely when multiple risk factors are involved

Developmental resilience

Successful development of a child in spite of multiple and seemingly overwhelming developmental hazard

*Resilient children often have two factors in their favor:

1. Certain personal characteristics, especially intelligence

2. Responsive care from someone

What did the Minnesota Study of Twins Reared Apart find?

One set of identical twins raised in different families showed many striking similarities, both physical and behavioral, including a similar work history and their roles as volunteer firemen

Epigenetics

The way in which experience alters gene expression (genes code for proteins)

*The reason why twins who share the same DNA will not share the same pattern of gene expression

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 surroundings (including prenatal experience) other than genes

Chromsomes, DNA, genes

Chromosomes. = molecules of DNA that transmit genetic information

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

What three mechanisms promote genetic variability among individuals?

1. Random assortment of chromosomes in the formation of egg and sperm: During gamete division, the 23 pairs of chromosomes are shuffled randomly, with chance determining which member of each pair goes into each new egg or sperm cell

2. Crossing over: the process by which sections of DNA switch from one chromosome to the other when gametes divide

3. Mutation: a change in a section of DNA

Sex chromosomes

The chromosomes (X and Y) that determine an individual's designated sex at birth

Endophenotypes

Intermediate phenotypes, including the brain and nervous systems, that do not involve overt behavior

Regulator genes

Genes that control the activity of other genes (by switching them on or off during different times in development)

Alleles, dominant, recessive

Two or more different forms of a gene

Dominant = the allele that, if present, gets expressed

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

Homozygous, heterozygous

Homozygous = having two of the same allele for a trait

Heterozygous = having two different alleles for a trait (the dominant allele will be expressed)

Polygenic inheritance pattern

Many different genes contribute to any given phenotypic outcome

*Despite the traditional emphasis given to the dominant-recessive pattern of inheritance, it actually pertains to relatively few human traits

Genetic nurture

Phenomenon in which non-transmitted parents alleles play an important role in the creation of the child's environment

Epigenetics

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

Although the structure of the genetic code remains "fixed" during one's lifetime, the expression* of the genetic code is altered

*The epigenetic mechanism most commonly studied in humans is methylation, which silences genetic expression

Carrier genetic testing

Genetic testing used to determine whether prospective parents are carriers of specific disorders prior to pregnancy

*Results may cause some carriers to opt for in vitro fertilization

Prenatal testing

Genetic testing used to assess the fetus's risk for genetic disorders

Newborn screening

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

*Newborns receive a tiny pinprick to their heel to get a blood sample, which is then tested for 30-50 different genetic and non-genetic disease biomarkers

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

Family study

The mainstay of quantitative behavior genetics; attempts to determine whether phenotypic traits are correlated with the degree to which people are genetically related - parents and children, identical and fraternal twins, non-twin siblings, or adoptive family members

Equal environments assumption

Idea that for twins who grow up together (both DZ and MZ), the degree of similarity of the environment is generally assumed to be equal

-The claim is that since both types of twins (DZ and MZ) grew up in the same environment, any differences seen between them can be assumed to be purely from genetic causes

What are the problems with the equal environments assumption?

-Parents of MZ twins may treat them more similarly than parents of DZ twins

-Even among MZ pairs, there is notable differences in the degree of placental sharing (known as chorionicity)

What is the ideal behavior genetics design?

Adoptive twin study, in which identical twins who grew up. together are compared to identical twins who were separated shortly after birth and raised apart

Heritability

A statistical estimate of how much of the measured variance on a phenotypic trait among individuals in a given population is attributable to genetic differences among those individuals

-Is conducted on many pairs of twins within the same area (ex. in New York)

*Problem with heritability estimates is that they necessarily reflect the environments of the population from which they derived (for example, heritability estimates may appear larger within populations with more homogenous environments)

As twins get older, the degree of variance in intelligence accounted for by their genetic similarity _________.

Increases

*These results are consistent with the idea that people actively construct their own environment

What are two examples of molecular genetics research designs?

1. Genome-wide association studies (GWAS)

2. Genome-wide complex trait analysis