Thinking Critically with Psychological Science & Research Design

Vocabulary practice flashcards covering psychological research methods, experimental design, sampling techniques, statistical concepts, types of bias, validity, and reliability.

Hindsight Bias

The tendency to believe, after learning an outcome, that one would have foreseen it; also known as the "I-knew-it-all-along" phenomenon.

Overconfidence

The tendency to think we know more than we actually do.

Critical Thinking

Thinking that does not blindly accept arguments and conclusions by examining assumptions, discerning hidden values, and evaluating evidence.

Theory

An explanation using an integrated set of principles that organizes and predicts observations.

Hypothesis

A testable prediction, often implied by a theory.

Null-Hypothesis

A hypothesis that addresses what occurs if the research prediction is wrong, stating that there is no effect or relationship.

Experiment

A research design used to establish cause-and-effect relationships by manipulating specific factors while controlling others.

Demand Characteristics

Cues or features in an experiment that lead participants to guess the aim of the study and alter their behavior accordingly.

Placebo Effect

Experimental results caused by participant expectations alone or belief in a treatment rather than the treatment itself.

Correlational Study

A study that measures the statistical relationship between two naturally occurring variables to assess how well one predicts another without manipulating factors.

Correlation Coefficient

A statistical measure of the extent to which two factors vary together, indicating direction (positive or negative) and strength on a scale from $0.00$ to $1.00$.

Cross-Sectional Study

A research design in which data is collected from participants at a single point in time.

Longitudinal Study

A research design in which data is collected repeatedly from the same subjects over an extended period of time.

Case Study

An in-depth, deep-dive examination of a single individual, group, or event.

Replication

Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding generalizes.

Survey

A technique for ascertaining self-reported attitudes or behaviors of people, usually by questioning a representative, random sample.

Independent Variable (IV)

The experimental factor that is manipulated by the researcher to study its effect.

Dependent Variable (DV)

The experimental factor that is measured and may change in response to manipulations of the independent variable.

Experimental Condition

The condition of an experiment that exposes participants to the treatment or manipulated independent variable.

Control Condition

The condition of an experiment where the independent variable is not applied, serving as a comparison baseline.

Extraneous Variable

Other factors that can potentially affect research results which researchers attempt to control in advance.

Confounding Variable

An extra factor directly affecting the dependent variable, often identified after results are gathered.

Operationalization

The precise specification of how a variable will be measured or quantified in a study.

Random Sampling

A sampling method in which every member of the target population has an equal chance of being selected.

Opportunity Sampling

A sampling technique that selects individuals who are readily available at the time of the study.

Snowball Sampling

A sampling method where existing study participants recruit future participants from among their acquaintances.

Stratified Sampling

A sampling technique where sample proportions match the specific sub-group percentages of the target population.

Cluster Sampling

A sampling technique where the population is divided into groups or clusters, and entire groups are selected.

Systematic Sampling

A sampling method where participants are chosen according to a fixed interval, such as every $n\text{th}$ person from a list.

Quantitative Data

Research data expressed in numerical form.

Qualitative Data

Research data expressed in words, descriptions, or observations.

Primary Data

Data collected directly by the researcher specifically for the research study at hand.

Secondary Data

Data collected by someone other than the primary researcher for another purpose.

Mode

The most frequently occurring score in a distribution.

Mean

The arithmetic average of a distribution, obtained by adding all scores and dividing by the total number of scores.

Median

The middle score in a distribution, where half of the scores are above it and half are below it.

Range

A measure of variability calculated as the difference between the highest and lowest scores in a data set.

Standard Deviation

A measure of variability reflecting the average distance between every score and the mean, calculated as $\text{Standard deviation} = \sqrt{\frac{\text{Sum of (deviations)}^2}{\text{Number of scores}}}$.

Normal Curve

A symmetrical bell-shaped distribution where approximately $68\%$ of scores fall within 1 standard deviation of the mean, and about $95\%$ fall within 2 standard deviations.

Descriptive Statistics

Statistical techniques used to summarize, organize, and describe data sets to make them understandable.

Inferential Statistics

Statistical procedures that assess the probability that sample results generalize to the larger population rather than occurring by chance.

Statistical Significance

A determination that an observed research result reflects a real-world effect rather than chance, typically defined as a probability of $5\%$ ($p \le 0.05$) or less.

Biased Sample

A sample whose members differ systematically from the larger population the researcher intends to study.

Observer-Expectancy Effect

A bias that occurs when a researcher's expectations unconsciously influence measurements or participant behavior.

Subject-Expectancy Effect

A bias that occurs when a subject knows the study design and tries to produce the expected outcome.

Hawthorne Effect

The tendency for participants to change their behavior simply because they are aware of being watched.

Social Desirability Bias

The tendency of respondents to answer questions in a manner that will be viewed favorably by others rather than truthfully.

Publication Bias

The phenomenon where studies showing positive or statistically significant results are more likely to be published than studies with null findings (file drawer effect).

Reliability

The consistency and stability of research measurements or results across repeated trials.

Test-Retest Reliability

A measure of consistency determined by administering the same test twice over time to the same participants.

Inter-Rater Reliability

The degree of agreement among different raters or observers scoring the same phenomenon.

Internal Validity

The extent to which a study correctly tests its intended hypothesis without confounding variables influencing the outcome.

External Validity

The degree to which study results can be generalized to other people, settings, and contexts.

Ecological Validity

A specific type of external validity assessing whether experimental conditions reflect real-world environment and tasks.