AP PSYCH UNIT 0 VOCAB

Cultural norms

Shared rules or expectations within a social group about how people should think, feel, and behave.

Confirmation bias

The tendency to seek, interpret, and remember information that confirms our preexisting beliefs.

Hindsight bias

The “I‑knew‑it‑all‑along” tendency to believe, after learning an outcome, that it was predictable.

Overconfidence

When people overestimate the accuracy of their knowledge and judgments.

Independent variable (IV)

The factor that is deliberately manipulated by the researcher.

Dependent variable (DV)

The outcome that is measured; it changes in response to the IV.

Confounding variables

Unintended factors other than the IV that might influence the DV.

Random assignment

Assigning participants to groups by chance to reduce preexisting differences.

Case study

In‑depth examination of one person or a small group.

Correlation

A statistical measure of how two variables vary together.

Positive correlation

Both variables increase or decrease together.

Negative correlation

One variable increases while the other decreases.

Meta-analysis

A method that combines results from many studies to determine overall trends.

Naturalistic observation

Observing behavior in its natural environment without interference.

Hypothesis

A testable prediction about the relationship between variables.

Operational definitions

Clear, specific descriptions of how variables are measured or manipulated.

Replication

Repeating a study to see if results can be duplicated.

Measures of central tendency

Statistics that describe a typical score: mean, median, mode.

Measures of variation

Statistics that describe the spread of data: range, standard deviation.

Percentile rank

The percentage of scores that fall below a given score.

Mean

The arithmetic average.

Median

The middle score in a distribution.

Mode

The most frequent score(s).

Range

Difference between highest and lowest scores.

Normal curve

Symmetrical bell‑shaped distribution.

Positive skew

Distribution with a long tail to the right.

Negative skew

Distribution with a tail toward the left.

Bimodal distribution

A distribution with two peaks.

Standard deviation

Average distance of scores from the mean.

Regression toward the mean

Extreme scores tend to move closer to the average on retesting.

Sample

The subset of the population studied.

Population

The entire group the researcher is interested in.

Representative sample

A sample that reflects the characteristics of the population.

Random sampling

Each member of a population has an equal chance of being selected.

Generalizing

Applying findings from a sample to the larger population.

Experimental group

The group exposed to the IV.

Control group

The group not exposed to the IV; serves as a comparison.

Placebo

An inert treatment given instead of the real IV to control expectations.

Placebo effect

Changes in behavior or feelings due to expectations about a treatment rather than the treatment itself.

Single-blind study

Participants don’t know which group they’re in.

Double-blind study

Neither participants nor researchers know group assignments.

Experimenter bias

When researchers unintentionally influence outcomes based on expectations.

Qualitative research

Research that focuses on describing characteristics or qualities.

Structured interviews

Preplanned questions asked in a systematic way to participants.

Quantitative research

Research that focuses on numerical data and statistical analysis.

Likert scales

A scale commonly used in surveys to measure attitudes or opinions.

Peer review

Scientists evaluate research before publication to ensure quality.

Scatterplot

A graph of dots showing the relationship between two variables.

Correlation coefficient

A number (–1 to +1) measuring strength and direction of a correlation.

Effect sizes

Indicates strength of a relationship or the magnitude of an effect.

Statistical significance

A mathematical indication that results are unlikely due to chance.

Third variable problem (in correlation)

When a hidden factor influences both variables in a correlation.

Institutional review

Review by an ethics board before research begins.

Informed consent

Participants must be told enough to choose whether to take part.

Informed assent

Minors agree to participate with partial understanding and guardian’s consent.

Protection from harm

Participants must be protected from physical/psychological harm.

Confidentiality

Researchers must keep participant data private.

Deception

Sometimes participants are misled for study purposes (ethics still apply).

Debriefing

Explaining the study and purpose afterward.