AP Psychology exam prep (kill me) 2025

Critical Thinking

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

Hindsight Bias

The tendency to believe, after learning an outcome, that one would have foreseen. (Also known as the 'I-Knew-It-All-Along 'phenomenon)

Peer Reviewers

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→Uses an "If… then,…" format.

Operational Definition

A carefully worded statement of the exact procedures (operations) used in a 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 or group is studied in depth to reveal universal principles.

Naturalistic Observation

A non-experimental technique of observing and recording behavior in naturally occurring situations without trying to manipulate or 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 responding in ways they presume a researcher expects or wishes.

Self Reporting Bias

Bias when people report their behavior inaccurately.

Sampling Bias

A flawed sampling process that produces an unrepresentative sample.

Random Sample

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

Population

All those in a group being studied, from which 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

The statistical index of the relationship between two things (from -1.00 to +1.00).

Variable

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

Scatter Plot

A graphed cluster of dots, each of which represents the values of two variables.

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) to the average.

Experiment

A research method in which an investigator manipulates one or more factors, to observe the effect on some behavior or mental process.

Experimental Group

In an experiment, the group that is exposed to the treatment, that is, to one version of the IV.

Control Group

In an experiment, the group that is 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 differences between the 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.

Placebo Effect

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

Independent Variable

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

Confounding Variable

In an experiment, a factor other than the factor being studied might influence a study's results.

Experimenter Bias

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

Dependent Variable

In an experiment, the outcome that is measured; is 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 postexperimental 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 central tendency and measures of variation.

Histogram

A bar graph depicting a frequency distribution.

Mode

The most commonly recurring number in a set of Data.

Mean

The average for a set of data. (Add all numbers and divide by how many data points you have)

Median

The number of data that lies in the middle of your data set.

Percentile Rank

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

Skewed Distribution

A representation of scores that lack symmetry.

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 curve 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.

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

Statistical Significance

A statistical statement of how likely it is that a result (such as a difference between samples) occurred by chance

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.

Nature-Nurture issue

There is longstanding controversy over the relative contributions of genes and experience to developing psychological traits and behaviors. Today's science views traits and behaviors as arising from the interaction of nature and nurture.

Charles Darwin

known as the architect of the theory of evolution by natural selection.

Natural selection

The principle that the inherited traits enabling an organism to survive and reproduce in a particular environment will 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 genetic and environmental influences on behavior.

Mutations

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

Environment

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

Heredity

The genetic transfer of characteristics from parents to offspring.

Genes

The biochemical units of heredity.

Genome

The complete instructions for making an organism.

Identical (Monozygotic) twins

Individuals developed from a single fertilized egg that split in two, creating two genetically identical organisms.

Fraternal (dizygotic) twins

Individuals who developed from separate fertilized eggs. They are genetically no closer than ordinary siblings, but they share a prenatal environment.

Interactions

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

Epigenetics

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, consists of all the nerve cells of the peripheral and central nervous systems.

Central Nervous System (CNS)

The brain and spinal cord.

Peripheral Nervous System (PNS)

The sensory and motor neurons connect the central nervous system (CNS) to the rest of the body.

Nerves

Bundled axons form neural cables connecting the central nervous system with muscles, glands, and sensory organs.

Sensory Neurons

Neurons carry incoming information from the body's tissues and sensory receptors to the brain and spinal cord.

Motor Neurons

Neurons carry outgoing information from the brain and spinal cord to the muscles and glands.

Interneurons

Neurons within the brain and spinal cord; 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.

Autonomic Nervous System (ANS)

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart).

Sympathetic Nervous System

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

Parasympathetic Nervous System

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

Reflexes

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

Neurons

A nerve cell; is the basic building block of the nervous system.

Cell Body

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

Dendrite

A neuron's often bushy, branching extensions receive and integrate messages, conducting impulses toward the cell body.

Axon

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

Myelin Sheath

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

Glial Cells

Cells in the nervous system that support, nourish, and protect neurons

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 occurs after a neuron has fired; subsequent action potentials 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 axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons.

Reuptake

A neurotransmitter's reabsorption by the sending neuron.

Endorphins

"Morphine within" — natural, opioid-like neurotransmitters linked to pain control and 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; is 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 significant life disruption.

Depressants

Drugs that reduce neural activity and slow body functions.

Tolerance

A condition, resulting from persistent use of a drug, characterized by a markedly diminished effect with regular use of the same dose of the drug or by a need to increase the dose markedly over time to achieve the same desired effect.

Addiction

A state of psychological and/or physical dependence on the use of drugs or other substances, such as alcohol, or on activities or behaviors.