Psychological Research Methods & Concepts

Cultural norms

The societal norms, values, and expectations that influence behavior and mental processes.

Confirmation bias

The tendency to search for, interpret, favor, and recall information in a way that confirms one's preexisting beliefs or hypotheses.

Hindsight bias

The inclination, after an event has occurred, to see the event as having been predictable, despite there being little or no objective basis for predicting it.

Overconfidence

The tendency to have more confidence in one's own abilities or knowledge than is objectively reasonable.

Random assignment

Assigning participants to experimental and control conditions by chance to minimize preexisting differences between those assigned to the different groups.

Case study non-experimental

An in-depth study of a single individual or a small group that provides detailed descriptive information but cannot be used to establish cause-and-effect relationships.

Correlation non-experimental

A research method that examines how variables are naturally related in the real world, without any attempt by the researcher to alter them.

Meta-analysis non-experimental

A statistical technique for combining the findings from independent studies to identify patterns of results across studies.

Hypothesis

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

Operational definitions

Clear, specific definitions of variables or procedures used in a research study.

Independent variable (IV)

The variable that is manipulated or changed in an experiment to observe its effects on the dependent variable.

Dependent variable (DV)

The variable that is measured or observed in an experiment and is expected to be influenced by the independent variable.

Confounding variables

Variables other than the independent variable that may influence the results of an experiment.

Population

The entire group of individuals or instances about whom the researcher wants to draw conclusions.

Representative sample

A subset of the population that accurately reflects the characteristics of the whole population.

Random sampling

A sampling technique where every member of the population has an equal chance of being selected for the sample.

Sampling bias

A bias that occurs when a sample is not representative of the population it is intended to represent.

Experimental group

The group in an experiment that receives the treatment or intervention being studied.

Control group

The group in an experiment that does not receive the treatment and is used as a comparison to evaluate the effects of the treatment.

Placebo/Placebo Effect

A substance or treatment that has no therapeutic effect, often used as a control in experiments.

Single-blind

An experimental procedure in which the participants are unaware of which participants received the treatment and which did not.

Double-blind

An experimental procedure in which both the participants and the researchers are unaware of which participants received the treatment and which did not.

Qualitative

Research methods that focus on understanding human behavior from participants' perspectives, using methods such as interviews or observations.

Quantitative

Research methods that focus on quantifying and analyzing data using statistical techniques.

Replication

Repeating a research study to confirm or disconfirm the results of a previous study.

Variables

Factors that can change or vary in an experiment.

Survey technique

A method of collecting data by asking people a series of questions.

Self-report bias

A bias that occurs when participants inaccurately report their thoughts, feelings, or behaviors in a study.

Experimenter Bias

A bias that occurs when a researcher's expectations or preferences influence the results of a study.

Peer review

The process by which a scholarly work is reviewed by other experts in the field before it is published.

Confidentiality

Protecting the privacy of research participants by keeping their information secure and undisclosed.

Deception

Misleading participants about the true purpose of a study or the procedures involved.

Research confederates

Individuals who are aware of the true purpose of a study and help the researcher achieve the study's goals.

Debriefing

Providing participants with a full explanation of the study's purpose and methods after its completion.

Measure of central tendency

A single value that represents the center of a data set, including the mean, median, and mode.

Range

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

Normal curve

A symmetrical, bell-shaped curve that represents the distribution of scores in a population.

Measures of variation

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

Skewness

A measure of the asymmetry of a distribution, indicating whether the data is concentrated on one side.

Bimodal distribution

A distribution with two distinct peaks or modes.

Standard deviation

A measure of the dispersion of scores around the mean in a data set.

Percentile rank

The percentage of scores that fall below a specific score in a distribution.

Scatterplot

A graph that shows the relationship between two variables, with each data point representing an individual.

Correlation coefficient

A statistical measure that indicates the strength and direction of a relationship between two variables.

Effect size

A measure of the strength of the relationship between two variables in a study.

Statistical significance

The likelihood that a result or relationship is not due to chance.

Mean

The average of a set of scores, calculated by adding all scores and dividing by the number of scores.

Median

The middle score in a data set when scores are arranged in numerical order.

Mode

The most frequently occurring score in a data set.