Every SINGLE AP Psychology Term (Updated)

Independent Variable

The variable that is manipulated by the researcher.

Dependent Variable

The variable that is measured by the researcher.

Random Assignment

Assigning participants to experimental and control groups randomly.

Non-experimental Methodology

Research methods that do not involve manipulating variables.

Case Study

An in-depth investigation of a single subject or group.

Correlation

A statistical measure of the relationship between two variables.

Meta-Analysis

A statistical technique for combining the results of multiple studies.

Naturalistic Observation

Observing behavior in its natural setting.

Hypothesis

A testable prediction about the relationship between two or more variables.

Falsifiable

A hypothesis that can be disproven.

Operational Definition

A precise definition of a variable in terms of how it is measured.

Replicate

To repeat a study to see if the same results are obtained.

Confounding Variable

A variable that is not of interest to the researcher but that may influence the results of the study.

Sample

A subset of a population.

Population

The entire group of individuals that a researcher is interested in studying.

Representative Sample

A sample that accurately reflects the characteristics of the population.

Random Sampling

A method of selecting participants from a population in which each individual has an equal chance of being selected.

Convenience Sampling

A method of selecting participants based on their availability.

Sampling Bias

A systematic error in a sample that results in a biased estimate of the population parameter.

Generalized

To apply the findings of a study to a larger population.

Experimental Group

The group of participants who receive the treatment.

Control Group

The group of participants who do not receive the treatment.

Placebo

A substance or treatment that has no therapeutic effect.

Placebo Effect

A phenomenon in which people experience a change in their condition because they believe they are receiving a treatment, even if the treatment is ineffective.

Single-Blind Study

A study in which the participants do not know whether they are in the experimental or control group.

Double-Blind Study

A study in which neither the participants nor the researchers know who is in the experimental or control group.

Experimenter Bias

A researcher's expectations influencing the results of a study.

Social Desirability Bias

The tendency for people to answer questions in ways that make them look good.

Qualitative Research

Research that collects data in non-numerical form.

Structured Interviews

Interviews that follow a predetermined set of questions.

Quantitative Research

Research that collects data in numerical form.

Likert Scales

Rating scales used to measure attitudes or opinions.

Correlational Study

A study that examines the relationship between two or more variables.

Directionality Problem

The problem of determining which variable causes which.

Self-Report Bias

The tendency for people to be inaccurate when reporting on their own behavior or attitudes.

Peer Review

The process of having research evaluated by other experts in the field.

Institutional Review Board (IRB)

A committee that reviews research proposals to ensure that they are ethical.

Ethics in Research

Guidelines for conducting research ethically.

Informed Consent/Assent

Obtaining permission from participants or their legal guardians before conducting research.

Protection from Harm

Minimizing the risk of harm to participants.

Confidentiality/Anonymity

Protecting the privacy of participants.

Deception/Confederates

Using deception to manipulate participants' behavior.

Debriefing

Explaining the purpose of the study to participants and answering any questions they may have.

Central Tendency

A measure of the center of a distribution.

Variation

The spread of scores in a distribution.

Percentile Rank

The percentage of scores that fall below a particular score.

Mean

The average of a set of scores.

Median

The middle score in a set of scores.

Mode

The most frequently occurring score in a set of scores.

Range

The difference between the highest and lowest scores in a set of scores.

Normal Curve

A bell-shaped curve that represents a normal distribution.

Skewed Curve

A curve that is not symmetrical.

Bimodal Distribution

A distribution with two peaks.

Standard Deviation

A measure of the variability of a set of scores.

Regression Toward the Mean

The tendency for extreme scores to move closer to the mean over time.

Neuron

A nerve cell.

Glial Cell

A cell that supports and protects neurons.

Reflex Arc

A simple neural pathway that controls a reflex.

Sensory Neuron (Afferent)

A neuron that carries information from the senses to the spinal cord or brain.

Motor Neuron (Efferent)

A neuron that carries information from the spinal cord or brain to the muscles.

Interneuron

A neuron that connects sensory and motor neurons.

All-or-None Law

The principle that a neuron either fires or it doesn't.

Depolarization

The process of making the inside of a neuron more positive.

Refractory Period

The time period after a neuron fires during which it cannot fire again.

Resting Potential

The electrical charge of a neuron at rest.

Reuptake

The process by which neurotransmitters are reabsorbed by the sending neuron.

Stimulus Threshold

The minimum level of stimulation required to trigger a neural impulse.

Multiple Sclerosis

A disease that attacks the myelin sheath of neurons.

Myasthenia Gravis

A disease that attacks the receptors for acetylcholine.

Action Potential

A neural impulse.

Neurotransmitter

A chemical messenger that travels across the synapse between neurons.

Excitatory Message

A message that increases the likelihood that a neuron will fire.

Inhibitory Message

A message that decreases the likelihood that a neuron will fire.

Dopamine

A neurotransmitter involved in pleasure, reward, and movement.

Serotonin

A neurotransmitter involved in mood, appetite, and sleep.

Norepinephrine

A neurotransmitter involved in alertness and arousal.

Glutamate

An excitatory neurotransmitter involved in learning and memory.

GABA

An inhibitory neurotransmitter involved in anxiety and sleep.

Endorphins

Neurotransmitters involved in pain relief and pleasure.

Substance P

A neurotransmitter involved in pain perception.

Acetylcholine

A neurotransmitter involved in muscle contraction and memory.

Endocrine System

A system of glands that secrete hormones.

Hormone

A chemical messenger that is secreted into the bloodstream.

Adrenaline

A hormone that prepares the body for action.

Leptin

A hormone that helps regulate appetite.

Ghrelin

A hormone that stimulates appetite.

Melatonin

A hormone that regulates sleep.

Oxytocin

A hormone involved in bonding and social behavior.

Psychoactive Drug

A drug that alters mood, perception, or behavior.

Agonist

A drug that mimics the effects of a neurotransmitter.

Antagonist

A drug that blocks the effects of a neurotransmitter.

Stimulants

Drugs that increase alertness and arousal.

Depressants

Drugs that decrease alertness and arousal.

Hallucinogens

Drugs that alter perception and sensory experiences.

Opioids

Drugs that reduce pain and produce euphoria.

Tolerance

The need for increasing doses of a drug to achieve the same effect.

Addiction

A chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences.

Withdrawal

Physical and psychological symptoms that occur when a person stops using a drug.

Central Nervous System (CNS)

The brain and spinal cord.

Brain

The organ that controls thought, emotion, and behavior.