AP Psychology Final, Jo, University Highschool, 2026,

Terms taken directly from 2026 Study Guide

Theory

Well-tested explanation that organizes and predicts behavior.

Hypothesis

Testable prediction about the relationship between variables.

Independent Variable

Variable manipulated by the researcher.

Dependent Variable

Variable measured; affected by the IV.

Control Group

Group that does not receive treatment.

Experimental Group

Group that receives treatment.

Empirical Investigation

Research based on observation or experimentation.

Scientific Method

Process of hypothesis → test → analyze → conclude.

Correlation

Measure of relationship between variables (no causation).

Correlation Coefficient

Number from -1 to +1 showing strength/direction.

Positive Correlation

Variables increase/decrease together.

Negative Correlation

One increases, the other decreases.

Zero Correlation

No relationship.

Operational Definition

Exact way variables are measured.

Single-Blind Study

Participants unaware of group assignment.

Double-Blind Study

Both participants and researchers unaware.

Confounding Variable

Outside factor affecting results.

Experimenter Bias

Researcher expectations influence results.

Confirmation Bias

Tendency to favor info that supports beliefs.

Random Sampling

Selecting participants randomly from population.

Random Assignment

Randomly assigning to groups.

Representative Sample

Accurately reflects population.

Generalizable

Results apply broadly to population.

Replication

Repeating a study to verify results.

Ethics

Protect participants (consent, no harm, debriefing).

Institutional Review Board (IRB)

Ensures ethical research.

Malfeasance

Harmful or unethical actions.

Nonmalfeasance

Do no harm principle.

Naturalistic Observation

Observing in natural setting.

Longitudinal Study

Same group over time.

Cross-Sectional Study

Different groups at one time.

Cohort Sequential Study

Combination of longitudinal and cross-sectional.

Frequency Distribution

Shows how often values occur.

Histogram

Bar graph of frequency distribution.

Scatterplot

Graph of correlation.

Skew

Distortion of data distribution.

Mean

Average score.

Median

Middle score.

Mode

Most frequent score.

Range

Difference between highest and lowest.

Standard Deviation

Spread of data from mean.

Statistical Significance

Results unlikely due to chance.

Inferential Statistics

Drawing conclusions about population.

Placebo

Inactive treatment.

Placebo Effect

Improvement due to expectation.

Quantitative Data

Numerical data.

Qualitative Data

Descriptive data.

Neuron

Nerve cell that transmits information.

Dendrites

Receive messages.

Axon

Sends messages.

Myelin Sheath

Speeds transmission.

Resting Potential

Neuron at -70mV (not firing).

Action Potential

Neural impulse firing.

All-or-None

Neuron fires fully or not at all.

Neurotransmitters

Chemical messengers between neurons.

Agonist

Increases neurotransmitter activity.

Antagonist

Decreases neurotransmitter activity.

Central Nervous System

Brain and spinal cord.

Peripheral Nervous System

All other nerves.

Sympathetic NS

Arouses (fight-or-flight).

Parasympathetic NS

Calms (rest-and-digest).

Endocrine System

Glands that release hormones.

Broca’s Area

Speech production.

Wernicke’s Area

Language comprehension.

Lobes

Frontal (decision), Parietal (touch), Occipital (vision), Temporal (hearing).

Split Brain

Corpus callosum severed; hemispheres act independently.

PET Scan

Measures brain activity using radioactive glucose.

MRI

Structure imaging.

fMRI

Shows brain activity in real time, measures changes in blood flow

EEG

Electrical brain activity.

Circadian Rhythm

24-hour biological clock.

REM Sleep

Dreaming stage.

Sleep Disorders

Insomnia, narcolepsy, sleep apnea.

Threshold

Minimum stimulus needed to detect.

Transduction

Conversion of stimulus into neural signal.

Rods

Detect light/dark.

Cones

Detect color.

Trichromatic Theory

RGB cones detect color.

Opponent Process Theory

Opposing colors (red/green).

Sensory Adaptation

Reduced sensitivity over time.

Schema

Mental framework.

Assimilation

Fit info into existing schema.

Accommodation

Adjust schema.

Heuristic

Mental shortcut.

Algorithm

Step-by-step problem solving.

Functional Fixedness

Inability to see new uses.

Insight

Sudden realization.

Priming

Unconscious activation of associations.

Inattentional Blindness

Missing obvious stimuli.

Encoding

Getting info into memory.

Storage

Keeping info.

Retrieval

Getting info out.

Sensory Memory

Brief initial memory.

Short-Term Memory

Temporary (7±2 items).

Long-Term Memory

Permanent storage.

Recall

Retrieve without cues.

Recognition

Identify with cues.

Retroactive Interference

New info disrupts old.

Proactive Interference

Old info disrupts new.

Ebbinghaus Forgetting Curve

Rapid memory loss over time.