AP Psych Unit 0: Science Practices

Psychology

The scientific study of behavior and mental processes, using systematic methods to understand how people think, feel, and act.

Critical thinking

The process of evaluating information objectively, examining assumptions, evidence, and conclusions to form reasoned judgments without bias.

Hindsight bias

The tendency to believe, after an event has occurred, that one would have predicted or known the outcome in advance.

Confirmation bias

The tendency to seek, interpret, and remember information that confirms one's preconceptions while ignoring contradictory evidence.

Overconfidence

The tendency to be more confident in one's abilities or judgments than is justified by accuracy, leading to errors in decision-making.

Peer review

The process where experts in the field evaluate a research study's methods, results, and conclusions before publication to ensure quality and validity.

Theory

An organized set of principles that explains observed phenomena and predicts future outcomes based on empirical evidence.

Hypothesis

A testable prediction about the relationship between variables, derived from a theory, that can be supported or refuted through research.

Falsifiable

The quality of a hypothesis or theory that allows it to be tested and potentially disproven by empirical evidence.

Generalizability

The extent to which research findings from a sample can be applied to the broader population from which the sample was drawn.

Operational definition

A precise description of how variables are measured or manipulated in a study, ensuring clarity and replicability.

Replication

Repeating a research study with different participants or in different settings to verify the original findings.

Case study

An in-depth analysis of a single individual, group, or event to explore causation or illustrate general principles.

Meta-analysis

A statistical technique that combines results from multiple studies to identify overall trends and increase statistical power.

Naturalistic observation

A research method involving observing and recording behavior in naturally occurring settings without interference.

Survey

A research method using questionnaires or interviews to gather self-reported data from a sample about attitudes, beliefs, or behaviors.

Social desirability bias

The tendency of respondents to answer questions in a manner that will be viewed favorably by others, distorting results.

Self-report bias

Distortions in data from surveys or interviews due to inaccurate recall, dishonesty, or misunderstanding of questions.

Population

The entire group of individuals or instances about which researchers wish to draw conclusions in a study.

Sample

A subset of the population selected for study, used to make inferences about the larger group.

Random sample

A sample where every member of the population has an equal chance of being selected, reducing bias.

Representative sample

A sample that accurately reflects the characteristics of the population from which it is drawn.

Sampling bias

Error occurring when the sample is not representative of the population, leading to inaccurate generalizations.

Convenience sampling

Selecting participants who are easiest to access, often leading to biased results due to lack of representativeness.

Experimental methodology

A research approach that manipulates variables to establish cause-and-effect relationships under controlled conditions.

Non-experimental methodology

Research methods like correlations or observations that describe relationships without manipulating variables or establishing causation.

Correlation

A statistical measure of the extent to which two variables change together, indicating a relationship but not causation.

Positive correlation

A relationship where two variables increase or decrease together, shown by a correlation coefficient between 0 and +1.

Negative correlation

A relationship where one variable increases as the other decreases, shown by a correlation coefficient between -1 and 0.

Correlation coefficient

A numerical value between -1 and +1 that indicates the strength and direction of the relationship between two variables.

Variable

Any characteristic or factor that can vary or change within a study, such as age, temperature, or behavior.

Scatterplot

A graph that displays the relationship between two variables, with each point representing a pair of values.

Illusory correlation

The perception of a relationship between variables where none exists, often due to selective attention or expectation.

Directionality problem

The ambiguity in correlational studies about which variable influences the other or if the relationship is bidirectional.

Third variable problem

When a correlation between two variables is actually caused by an unmeasured third variable.

Regression toward the mean

The tendency for extreme scores to move closer to the average upon retesting, due to random variation.

Experiment

A research method where variables are manipulated to determine cause-and-effect relationships.

Experimental group

The group in an experiment that receives the treatment or manipulation of the independent variable.

Control group

The group in an experiment that does not receive the treatment, used as a baseline for comparison.

Independent variable

The factor manipulated by the researcher to observe its effect on the dependent variable.

Dependent variable

The outcome measured in an experiment, expected to change as a result of the independent variable.

Random group assignment

Assigning participants to experimental or control groups by chance to minimize preexisting differences.

Single-blind procedure

An experimental design where participants do not know if they are in the treatment or control group to reduce bias.

Double-blind procedure

An experimental design where neither participants nor researchers know who is in the treatment or control group.

Placebo

An inert substance or treatment given to the control group to mimic the experimental treatment.

Placebo effect

Improvement in condition due to participants' expectations rather than the actual treatment.

Confounding variable

An extraneous factor that varies systematically with the independent variable, potentially affecting results.

Experimenter bias

When a researcher's expectations influence the study's outcome, often unconsciously.

Validity

The extent to which a test or experiment measures what it is intended to measure or achieves accurate results.

Quantitative research

Research that collects numerical data to test hypotheses, often using statistics for analysis.

Qualitative research

Research that collects non-numerical data, such as interviews or observations, to understand experiences or themes.

Likert scale

A rating scale used in surveys where respondents indicate agreement or disagreement on a symmetric scale.

Structured interview

An interview with predetermined questions asked in a fixed order to ensure consistency across participants.

Institutional review

The process where an ethics committee evaluates research proposals to ensure they meet ethical standards.

Informed consent

Participants' voluntary agreement to participate in research after being informed of procedures, risks, and benefits.

Informed assent

Agreement from minors or those unable to give full consent, often alongside parental consent.

Protection from harm

Ethical principle requiring researchers to minimize physical or psychological risk to participants.

Confidentiality

Keeping participants' information private and not disclosing it without permission.

Anonymity

Ensuring participants' identities are not known, even to researchers, to protect privacy.

Research Confederates

Actors who pose as participants or bystanders in a study to manipulate situations without real participants' knowledge.

Debriefing

Post-study explanation to participants about the research purpose, deceptions, and any concerns addressed.

Deception

Withholding information or misleading participants about the study's true purpose, used only when necessary and ethically justified.

Measure of central tendency

Statistical measures that summarize a data set by identifying a single value as representative of the middle.

Mean

The arithmetic average of a set of numbers, calculated by summing values and dividing by the count.

Median

The middle value in a sorted list of numbers, separating the higher and lower halves.

Mode

The most frequently occurring value in a data set.

Percentile rank

The percentage of scores in a distribution that a specific score is higher than or equal to.

Skewed distribution

A data distribution that is asymmetrical, with most values clustered at one end and a tail extending to the other.

Positive skew

A skewed distribution where the tail extends to the right, with most values on the left and outliers on the high end.

Negative skew

A skewed distribution where the tail extends to the left, with most values on the right and outliers on the low end.

Normal curve

A symmetrical, bell-shaped distribution where most values cluster around the mean, with fewer at the extremes.

Bimodal distribution

A distribution with two distinct peaks or modes, indicating two prevalent values in the data set.

Measures of variability

Statistics that describe the spread or dispersion of values in a data set.

Range

The difference between the highest and lowest values in a data set, indicating spread.

Standard deviation

A measure of how much values in a data set deviate from the mean, indicating variability.

Inferential data

Statistical methods used to draw conclusions about a population based on sample data.

Statistical significance

The likelihood that a result is not due to chance, typically when p-value is less than 0.05.

Effect size

A measure of the strength or magnitude of a phenomenon or relationship in a study, independent of sample size.