Psychology Vocabulary Unit 0-5

Critical thinking

Thinking that does not automatically accept arguments and conclusions. Rather, it examines assumptions, appraises the source, discerns hidden biases, evaluates, and assesses conclusions.

Hindsight bias

The tendency to believe, after learning an outcome, that one would have foreseen it. (Also known as the I-knew-it-all-along phenomenon)

Peer reviews

Scientific experts who evaluate a research article’s theory, originality, and accuracy.

Theory

An explanation using an integrated set of principles that organizes observations and predicts behaviors or events.

Hypothesis

A testable prediction, often implied by a theory.

Falsifiable

The possibility that an idea, hypothesis, or theory can be disproven by observation or experiment.

Operation definition

A carefully worded statement of the exact procedures (operations) used in a research study.

Replication

Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding can be reproduced.

Case study

A non-experimental technique in which one individual pr group is studied in depth in the hopes of revealing universal principles.

Naturalistic observation

A non-experimental technique of observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.

Survey

A non-experimental technique for obtaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group.

Social desirability bias

Bias from people’s responding in ways they presume a researcher expects or wishes.

Self-report bias

Bias when people report their behavior inaccurately.

Sampling bias

Bias when people report their behavior inaccurately.

Random sample

A sample that fairly represents a population because each member has an equal chance of inclusion.

Population

All those in a group being studied, from which random samples may be drawn.

Correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.

Correlation coefficient

A statistical index of the relationship between two variables (from -1.00 to +1.00)

Variable

Anything that can vary and is feasible and ethical to measure.

Scatterplot

A graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation).

Illusory correlation

Perceiving a relationship where none exists or perceiving a stronger-than-actual relationship.

Regression toward the mean

The tendency for extreme or unusual scores or events to fall back (regress) toward the average.

Experiment

A research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant factors.

Experimental group

In an experiment, the group exposed to the treatment—that is, to one version of the independent variable.

Control group

In an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

Random assignment

Assigning participants to experimental and control groups by chance, thus minimizing preexisting difference between the different groups.

Single-blind procedure

An experimental procedure in which the research participants are ignorant (blind) about whether they have received the treatment or a placebo.

Double-blind procedure

An experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.

Effect

Experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumed is an active agent.

Independent variable

In an experiment, the factor that is manipulated; the variable whose effect is being studied.

Confounding variable

In an experiment, a factor other than the factor begin studied that might influence a study’s results.

Experimenter bias

Bias caused when researchers may unintentionally influence results to confirm their own beliefs.

Dependent variable

In an experiment, the outcome that is measured; the variable that may change when the independent variable is manipulated.

Validity

The extent to which a test or experiment measures or predicts what it is supposed to.

Quantitative research

A research method that relies on quantifiable, numerical data.

Qualitative research

A research method that relies on in-depth, narrative data that are not translated into numbers.

Informed consent

Giving potential participants enough information about a study to enable them to choose whether they wish to participate.

Debriefing

The post experimental explanation of a study, including its purpose and any deceptions, to its participants.

Descriptive statistics

Numerical data used to measure and describe characteristics of groups; include measures of cental tendency and measures of variation.

Histogram

A bar graph depicting a frequency distribution.

Mode

The most frequently occurring scores(s) in a distribution

Mean

The arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores.

Median

The middle score in a distribution; half the scores are above it and half the score are above it and half are below it.

Percentile rank

The percentage of scores that are lower than a given score.

Skewed distribution

A representation of scores that lack symmetry around their average value.

Range

The difference between the highest and lowest scores in a distribution.

Standard deviation

A computed measure of how much scores vary around the mean score.

Normal curve

A symmetrical, bell-shaped curved that describes the distribution of many types of data; most scores fall near the mean (about 68 percent fall within one standard deviation of it) and fewer and fewer scores lie near the extremes. (Also called a normal distribution)

Inferential statistics

Numerical data that allow one to generalize — to infer from sample data the probability of something being true of a population.

Meta-analysis

A statical procedure for analyzing the results of multiple studies to reach an overall conclusion.

Statistical significance

A statistical statement of how likely it is a result (such as a difference between samples) occurred by chance, assuming there is no difference between the populations being studied.

Effect size

The strength of the relationship between two variables. The larger the effect size, the more one variable can be explained by the other.

Psychology

The science of behavior and mental processes.

Nature-nurture issue

The longstanding controversy over the relative contributions that genes and experience make to the development of psychological traits and behaviors. Today’s science view traits and behaviors as arising from the interaction of nature and nurture.

Natural selection

The principle that the inherited traits enabling an organism to survive and reproduce in a particular environment will (in competition with other traits variations) most likely be passed on to succeeding generations.

Evolutionary psychology

The study of the evolution of behavior and the mind, using principles of natural selection.

Behavior genetics

The study of the relative power and limits of genetics and environmental influences of behavior.

Mutation

A random error in gene replication that leads to a change.

Environment

Every nongenetic influence, from prenatal nutrition to our experienced of the people and things around us.

Heredity

The genetic transfer of characteristics from parents to offspring.

Genes

The biochemical unit of heredity.

Genome

The complete instructions for making an organism.

Monozygotic Twins

Also known as identical twin, individuals who developed from a single fertilized egg that slit in two, creating two genetically identical organisms.

Dizygotic twins

Also known as fraternal twins, individuals from separate fertilized eggs. They are genetically no closer than ordinary siblings, but they shared a prenatal environment.

Interaction

The interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity)

Epigenetics

“Above” or “in addition to” (epi) genetics; the study of the molecular mechanisms by which environments can influence genetic expression. (without a DNA change)

Nervous system

The body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

CNS

Central Nervous System - the brain and spinal cord

PNS

Peripheral Nervous System - the sensory and motor neurons that connect the CNS to the rest of the body.

Nerves

Bundled axons that form neural cables connecting the CNS with muscles, glands, and sensory organs.

Afferent neurons

Also known as sensory neurons that carry incoming information from the body’s tissue and sensory receptors to the brain and spinal cord.

Efferent neurons

Also known as motor neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

Interneurons

Neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs.

Somatic Nervous System

The division of the peripheral nervous system that controls the body’s skeletal muscles. Also call the skeletal nervous system.

ANS

Autonomic Nervous System - The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division calms.

Sympathetic Nervous System

The division of the autonomic nervous system that arouses the body, mobilizing its energy.

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body, conserving its energy.

Reflex

A simple, automatic response to a sensory stimulus, such as the knee-jerk reflex.

Neuron

A never cell; the basic building block of the nervous system.

Cell body

The part of a neuron that contains the nucleus; the cell’s life-support center.

Dendrites

A neuron’s often bushy, branching extensions that receives and integrate messages, conducting impulses toward the cell body.

Axon

The segmented neuron extension that passes messages through its branches to other neurons or to muscles or glands.

Myelin sheath

A fatty tissue layer segmentally encasing the axons of some neurons; it enables vastly greater transmission speed as neural impulses hop from one node to the next.

Glial cells (glia)

Cells in the nervous systems that support, nourish, and protect neurons; they may also play a role in learning, thinking, and memory

Action potential

A neural impulse: a brief electrical charge that travels down an axon.

Threshold

The level of stimulation required to trigger a neural impulse.

Refractory period

In neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potential cannot occur until the axon returns to its resting state.

All-or-none response

A neuron’s reaction of either firing (with a full-strength response) or not firing.

Synapse

The junction between the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at the is junction is called the synaptic gap or synaptic cleft.

Neurotransmitters

Chemical messengers that cross the synaptic gap between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.

Reuptake

A neurotransmitter’s reabsorption by the sending neuron.

Endorphins

“Morphine within”; natural, opioid-like neurotransmitter linked to pain control and to pleasure.

Agonist

A molecule that increases a neurotransmitter’s action.

Antagonist

A molecule that inhibits or blocks a neurotransmitter’s action.

Endocrine system

The body’s “slow” chemical communication system; a set of glands and fat tissue that secrete hormones into the bloodstream.

Hormones

Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.

Psychoactive drug

A chemical substance that alters the brain, causing changes in perceptions and moods.

Substance use disorder

A disorder characterized by continued substance use despite resulting life disruption.

Depressant

Drugs that reduce neural activity and slow body functions.

Tolerance

The diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug’s effect.