Psychology

the scientific study of behavior and mental processes

Behavior

any movement or posture produced by an individual that influences its relationship

Not behavior

thinking, feeling, digesting, heartbeat, and hearing. These are internal/nonbehavioral processes, although they can affect behavior.

Mental processes

things such as thinking and feeling that cannot be directly observed. Mental processes are difficult to study because they cannot be directly observed or measured with certainty; brain activity can be correlated with thoughts or feelings but is not definitive, and people may not always report truthfully.

Tabula Rasa

the idea that at birth, human minds are a blank slate. This relates to the nature/nurture debate.

Structuralism

the idea that smaller elements combine to create the entire mental experience. Associated with Wilhelm Wundt and Edward Titchener.

Introspection

individuals describe their mental processes. A major problem is that self-reports can be subjective, inaccurate, and difficult to verify.

Gestalt psychology

the idea that the whole of perception is greater than the sum of its parts. Associated with Max Wertheimer.

Functionalism

asks how a behavior assists an organism with survival and/or reproduction. Based on Darwin’s evolution by natural selection and associated with William James.

Psychodynamic theory

behavior is the result of unconscious and often conflicting desires. Associated with Sigmund Freud.

Behaviorism

because the mind cannot be directly observed, only observable behavior should be studied and quantified. Associated with John B. Watson, B. F. Skinner, and Edward Thorndike.

Humanistic psychology

emphasizes free will, personal choice, motivation, and the idea that people are innately good until corrupted by society. Associated with Abraham Maslow and Carl Rogers.

Biological psychology

examines physical causes for behavior, including genetics, hormones, brain structures, and physiology.

Evolutionary psychology

considers the history of the species and asks how behavior assists survival or reproduction.

Cognitive psychology

the modern study of mental processes such as problem solving and memory, using experimentation to make inferences.

Developmental psychology

how behavior changes across the lifespan.

Social psychology

how other people affect thoughts and behavior.

Individual differences

studies varieties of behavior instead of averages; associated with personality.

Clinical psychology

identifies and treats abnormal behavior.

Scientific ideas are falsifiable

evidence could potentially show them to be false.

Scientific results should be replicable

other researchers should be able to perform the same test and obtain similar results.

Replication Project

an effort to repeat previously published psychology studies; many findings failed to replicate.

Critical-thinking steps

identify the claim; examine supporting evidence; consider alternative interpretations; identify useful additional data; reach the best conclusion

Goals of psychology

describe behavior, predict behavior, explain behavior, and control behavior.

Casual observations

are often unreliable, so formal testing is necessary.

Hypothesis

must be testable and falsifiable.

Peer review

scientists in the research community scrutinize papers before publication to evaluate methods and interpretations.

Descriptive research

includes case studies, surveys, and correlational studies.

Case study

detailed examination of one individual or a small number of individuals. A limitation is that unusual cases may not be representative.

Survey

questionnaire used to gather attitudes or opinions. Researchers need a representative sample. People may lie or answer inaccurately.

Correlational study

gathers data about a large group and looks for statistically significant trends. can include many subjects, so a few individuals are less likely to skew results. However, correlation does not necessarily demonstrate causation.

Correlation coefficient

a value from −1 to +1 indicating the strength and direction of a relationship between two variables.

Experiment

the researcher manipulates one or more variables and measures the effects while controlling other variables

Independent variable

the variable manipulated by the researcher.

Dependent variable

the variable potentially changed by the experimental manipulation.

Functional relationship

the cause-and-effect relationship between changes in the independent and dependent variables.

Placebo

a pill or treatment containing no active ingredients; it provides a comparison condition.

Double-blind procedure

neither the experimenter nor the subjects know who receives the active treatment until the study is over.

Experimenter expectancy effect

researchers’ expectations can unintentionally influence how groups are treated and the results.

Experimental group

receives the experimental treatment

Control group

does not receive the experimental treatment; provides a comparison.

Between-subjects experiment

different subjects are placed in groups that differ in the independent variable.

Within-subjects experiment

the same subjects are measured before and after treatment or under different conditions.

Confounding variable

any variable other than the independent variable that might affect the dependent variable.

Random assignment

subjects are assigned to treatment groups by chance.

Matching

potential subjects are paired or matched based on similarities, then placed in different groups.

Baseline measurement

the measurement taken before treatment in a within-subjects design.

Operational definition

a precise definition of a concept in terms of how it will be measured.

Meta-analysis

statistical analysis of a large number of studies to obtain a stronger overall conclusion.

Laboratory experiments

artificial environments with close control of variables.

Field/naturalistic experiments

conducted in natural environments; more authentic but less controlled.

Naturalistic observation

observing individuals in their natural environment to make correlations or predictions. Observer effect: people may behave differently when being watched.

Population

all people a scientist is interested in studying.

Sample

a subset of the population.

Representative sample

reflects the population as a whole.

Random sample

often used to avoid sampling bias.

Cross-sectional design

studies different groups of people of different ages. Cohort effects are historical factors affecting an age group that may explain results.

Longitudinal design

studies the same group at different points in time.

Practice effects

participants may improve because they become familiar with the test.

Attrition

individuals drop out or disappear from a longitudinal study.

Validity

whether a study measures the concept it is supposed to measure.

Reliability

how consistent a measurement is; across time and observers means an operational measure is consistent across repeated occasions and different observers.

Inter-rater reliability

the likelihood that two people taking the same measurement obtain the same result.

Descriptive statistics

help summarize patterns in data but cannot determine whether group differences are meaningful.

Frequency distribution

shows how many subjects belong in each category.

Mean

average. It is sensitive to extreme scores, called outliers.

Normal distribution

scores cluster around the mean in a symmetrical, bell-shaped pattern.

Median

the middle score; half the scores are higher and half are lower.

Mode

the most frequently occurring score. A distribution with more than one peak is multimodal.

Standard deviation

measures how tightly clustered or spread out scores are around the mean.

Statistical significance

indicates that there is only a small chance that observed differences resulted from chance.

Standard significance level

p ≤ .05. This means there is approximately a 5% chance of obtaining the results by chance under the relevant statistical assumption.

Important distinction

statistically significant does not necessarily mean practically important

Genotype

the complement of genes an organism has.

Gene

a segment of DNA in a particular location that codes for a functional molecule

Gene expression

only certain genes are expressed at a given time, even though all cells contain the organism’s complete DNA.

Phenotype

observable characteristics of an organism. results from the interaction between genetic makeup and environment.

Alleles

different versions of a gene; one allele is inherited from each parent.

Homozygous

having two copies of the same allele.

Heterozygous

having two different alleles.

Dominant allele

expressed regardless of the other allele.

Recessive allele

expressed only when the other allele is also recessive.

Sex chromosomes

the chromosome pair that differs between males and females; typically XX in females and XY in males.

Sex-linked inheritance

when a male inherits a deleterious recessive allele on his only X chromosome, it is expressed.

Epigenetics

the study of changes above the genome; the epigenome controls gene expression without changing the underlying DNA sequence.

Bisphenol A (BPA)

a chemical found in plastics used in the epigenetics example.

MAOA example

childhood abuse was associated with adult aggression especially among boys with the low-MAOA gene variant, illustrating gene–environment interaction.

Neurons

nerve cells that transmit and process information. The human brain has approximately 86 billion neurons.

Soma

cell body containing the nucleus.

Dendrites

branched structures that receive information from other neurons

Order of information being received to the body.

Dendrites → Soma → Axon → Terminal Buttons → Synapse

Axon

thin structure conveying information from the soma to terminal buttons.

• Terminal buttons: buds at the end of an axon that send information to another neuron.

• Terminal buttons: buds at the end of an axon that send information to another neuron.

Glial cells

non-neuronal cells that support neurons.

Astrocytes

form a supportive mesh and assist with passage of chemicals from blood to neurons.

Oligodendrocytes

wrap axons with myelin.

Myelin

fatty insulating substance that speeds neural communication.

Cortex

outer covering of the cerebrum. Gray matter consists largely of cell bodies and dendrites; white matter consists largely of myelinated axons

Action potential

electrical impulse traveling down the axon that leads to chemical communication. are all-or-none. Sodium enters first, then potassium exits, returning the neuron toward resting potential.

Synapse

junction/gap between neurons.

Resting potential

the negative electrical charge inside an axon compared with the outside; also called membrane potential.

Depolarization

the membrane becomes less polarized as the charge difference decreases.

Hyperpolarization

the membrane becomes more polarized as the charge difference increases.

Threshold

the point of depolarization at which an action potential is triggered.

Node of Ranvier

an unmyelinated portion of a myelinated axon.

Saltatory conduction

action potentials appear to jump from node to node.

Synaptic vesicles

contain neurotransmitters and fuse with the membrane to release them.

Receptors

channels in the receiving membrane that bind neurotransmitters.

Reuptake

neurotransmitters are taken back into the original neuron; some are broken down by enzymes.

Summation

excitatory and inhibitory signals combine near where the axon begins.

GABA (gamma-aminobutyric acid)

usually inhibitory. workhorse

Glutamate

usually excitatory; most sensory input except pain begins with glutamate. worhorse

Acetylcholine (ACh)

involved in all muscular movement, REM sleep, perceptual learning, and memory. Alzheimer’s disease is associated with fewer cholinergic neurons in the neocortex.

Norepinephrine

involved in attention and emotional tone; too little is associated with depression and too much can contribute to mania.

Dopamine

involved in movement, attention, learning, and reinforcement. Most drugs of abuse stimulate dopamine circuits.

Serotonin

involved in mood, aggression, appetite, arousal, pain perception, respiration, and dreaming. Too much has been linked to mania.

Endorphins

naturally occurring opioids involved in pain perception, defense responses, and reward; associated with runners’ high.

Opioids

drugs such as opium, morphine, heroin, and OxyContin that bind to endogenous opioid receptors.

Opiates

are natural drugs

CNS

central nervous system; brain and spinal cord.

PNS

peripheral nervous system; all nerves outside the brain and spinal cord.

Somatic nervous system

nerves connecting sense organs to the CNS and the CNS to muscles; includes voluntary movement.

Autonomic nervous system

controls involuntary muscles and supports homeostasis.

Sympathetic nervous system

fight-or-flight; increases heart rate and respiration and decreases digestion.

Parasympathetic nervous system

rest-and-digest; increases digestion and decreases heart rate and respiration.

Cerebrum

large area generally thought of as the brain; each hemisphere controls the opposite side of the body.

Cerebellum

hindbrain structure involved in coordinated movement, balance, and integrating sensory information with muscle movements.

Cerebral cortex

convoluted outer layer of the cerebrum.

Thalamus

relay station; almost all senses except olfaction pass through it before reaching the cortex. It also contributes to memory and consciousness.

Basal ganglia

structures involved in cognition and voluntary movement.

Broca's Aphasia

Knowing what you want to say, but can't say it.

Wernicke's Aphasia

Does not understand what you are saying, but can speak.

Huntington’s disease and Tourette’s syndrome

involve involuntary twitches or tics; Parkinson’s disease is caused by degeneration in basal ganglia structures.

Hypothalamus

involved in hormone production, metabolism, drives, and autonomic responses; think of the four Fs—fighting, feeding, fleeing, and mating.

Hippocampus

involved in forming long-term and spatial memories.

Amygdala

especially important for emotion toward negative stimuli, including fear.

Nucleus accumbens

involved in reward; pleasurable experiences increase dopamine in this area.

Corpus callosum

connects the two hemispheres and allows them to communicate.

Lateralized functions

performed primarily by one side of the brain.

Contralateral connections

most brain regions control or receive information from the opposite side of the body.

Right hemisphere

synthesizes information into a whole; spatial tasks, drawing, maps, complex construction, music, and negative emotions.

Left hemisphere

analyzes information and recognizes serial events; language, reading, writing, math, logic, and positive emotions.

Split-brain surgery

corpus callosotomy or commissurotomy, which severs the corpus callosum.

In the split-brain spoon example

the patient said she saw 'nothing' when asked about the spoon in the left visual field.

Alien hand syndrome

damage to the corpus callosum can cause a limb to act without conscious control.

Frontal lobe

contains the primary motor cortex and prefrontal cortex.

Occipital lobe

contains the primary visual area, V1.

Temporal lobe

processes auditory information and complex visual recognition, including faces.

Parietal lobe

contains the primary somatosensory cortex; processes touch, body position, and spatial information.

Association cortex

areas throughout the cortex that integrate information and support complex functions.

Prefrontal cortex

supports working memory, attention, emotional evaluation of outcomes, planning, strategies, associative learning, and context-appropriate behavior.

Phineas Gage’s Injury caused what?

personality change after damage to the frontal/prefrontal region and poor decision-making ability.

Orbitofrontal cortex

involved in decision making, emotion, and reward; it matures relatively late, around age 25.

Orbitofrontal damage

can cause inability to control impulses, reduced inhibition, aggression, irritability, and emotional dysregulation.

Contralateral neglect

right parietal damage can cause neglect of the left half of the body and world.

Normal distribution

about 68% within 1 standard deviation, 95% within 2, and 99.7% within 3.

Human brain

approximately 86 billion neurons

Standard significance level

p ≤ .05.

• Correlation coefficient range: −1 to +1.

• Correlation coefficient range: −1 to +1.

resting potential range

-70

equilibrium for potassium (K+)

+70

Orbitofrontal cortex matures at

age 25.