The Scientific Method & Studies (Week 2)

Fall 2025

Hindsight bias

the belief that an outcome was foreseeable (after it has occurred)

Experimenter bias

the experimenter’s expectations influence the outcome of a study

Variable

any property that can change over time

Operational Definition

a description of a property in concrete, measurable terms

Correlational Study

• Correlation doesn’t equal causation

• Issues with directionality and possible third variables

• Can be more ethical

Experimental Study

• can infer causation

• precise control over variable can eliminate alternative explanations

• highly controlled lab settings can make generalizations difficult

Social Learning Theory

Albert Bandura; people can learn from observation of others’ behavior

Independent Variable (IV)

Factor that is varied or manipulated

Dependent Variable (DV)

the behavior that is measured (and is expected to change as a function of change in the independent variables)

Random Assignment

assigning participants randomly to experimental conditions

Sample

a subset of the population

Random Sampling

Every person in the population has an equal likelihood of being selected

Convenience Sampling

this sample consists of people who are conveniently available for the study

Population

everyone in the group the experimenter is interested in

Placebo Effect

when receiving special treatment or something new affects human behavior

Hawthorne Effect

participants might change their behavior if they know they’re being studied

Replication

the process of repeating a study and fniding a similar outcome each time

Single-blind Study

Participants don’t know if they’re in the experimental or control group, but researchers do

Double-blind study

Neither the participant nor the experimenter knows if the participant is in the experimental or control group

Repeated Measure Design

The same participants experience all conditions of the experiment

Between-Subjects Design

different participants are assigned to each condition

Quasi-Experimental Design

An experiment, but no random assignment to groups

Longitudinal Study

Follows the same group of people over time to see how they change

Cross-Sectional Study

Compares different age or demographic groups at one time

Case Study

An in-depth study of one person or a small group

Naturalistic Observation

Watching behavior in its natural setting without interference

Clinical Trial

A controlled experiment used to test the effectiveness of treatments or medications (often in medical or psychological research)

Converging Operation

Using multiple methods or studies to investigate the same question

Stratified Sampling

The population is divided into subgroups (strata) (e.g., gender, race, age), and samples are taken proportionally from each group