AP PSYCH

Heuristics

Mental shortcuts the brain uses to process information quickly.

Cognitive Bias

Errors in thinking caused by heuristics.

Hindsight Bias

Believing 'I knew it all along' after an event occurs.

Overconfidence Bias

Thinking you’re more capable than you really are.

Operational Definition

Exact procedures used to define and measure variables.

Hypothesis

A testable prediction made before research.

Theory

An explanation supported by research and data.

Confounding Variable

An outside factor that can affect experiment results.

Placebo Effect

When improvement occurs due to belief in treatment, not the treatment itself.

Control Group

The group not exposed to the treatment.

Experimental Group

The group that receives the treatment.

Population in Research

The entire group being studied.

Representative Sample

A smaller group that accurately reflects the population.

Random Sampling

Everyone in the population has an equal chance of being chosen.

Stratified Sampling

Population divided into subgroups, random sample taken from each.

Sampling Bias

When the sample doesn’t reflect the whole population.

Correlation Studies

Studies that measure the relationship between two variables (but not causation).

Correlation Coefficient (r)

A statistic from -1.0 (perfect negative) to +1.0 (perfect positive). 0.0 = no relationship.

Strong r-value

r = ±0.7 to ±1.0.

Illusory Correlation

Perceiving a relationship when none exists.

Hawthorne Effect

People change behavior when they know they’re being observed.

Case Study

In-depth research on one person/group.

Meta-Analysis

Combining results of many studies to form a conclusion.

Surveys

Self-reported data through questions.

Quantitative Data

Statistical, objective data.

Qualitative Data

Subjective, opinion-based data.

Normal Distribution (Bell Curve)

Mean = 100, 85 = -1 z-score, 115 = +1 z-score.

Null Hypothesis

Prediction that nothing will happen/no relationship.

Alternative Hypothesis

Prediction that a relationship or effect exists.

Effect Size

The significance/impact of experimental results.

Institutional Review Board (IRB)

Ensures studies are ethical and safe.

Informed Consent

Participants understand and agree to the study.

Confidentiality in Research

Participants’ personal information must be kept private.

Debriefing

Explaining study details to participants afterward, especially if deception was used.