Psychology Research Methods and Experimental Design Key Concepts

Hypothesis

A testable prediction, often implied by a theory.

Operational definition

A statement of procedures used to define research variables.

Replication

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

Random sample

A sample that fairly represents a population because each member has an equal chance of inclusion.

Independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

Dependent variable

The outcome factor; the variable that may change in response to manipulation of the independent variable.

Confounding variable

Factors other than the independent variable that may cause a result.

Double-blind procedure

An experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or a placebo.

Experimental condition/group

The condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable.

Control condition/group

The condition of the experiment that contrasts with the experimental condition and serves as a comparison for evaluating the effect of a treatment.

Random assignment

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

Population

All the cases in a group, from which samples may be drawn for a study.

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).

Confirmation Bias

a tendency to search for information that supports our preconceptions and to ignore or distort contradictory evidence

Overconfidence

the tendency to be more confident than correct - to overestimate the accuracy of our beliefs and judgements

Experimenter Bias

the possibility that a researcher's expectations might skew the results of an experiment

Convenience Sampling

data is collected from an easily accessible and available group of people

Generalizability

is the degree to which you can apply the results of your study to a broader context

Qualitative Research Methods

is a method of inquiry used in various disciplines, including social sciences, education, and health, to explore and understand human behavior, experiences, and social phenomena.

Quantitative Research Methods

that relies on measuring variables using a numerical system, analyzing these measurements using any of a variety of statistical models, and reporting relationships and associations among the studied variables

Falsifiable Hypothesis

the hypothesis can be proved to be false

Placebo effect

experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent

Empirical methods

are a way of gaining information through direct and indirect observation as well as through experimentation.

Empirical evidence

can be analyzed quantitatively and qualitatively.

Experiments

are the only type of research method that can show a cause and effect relationship.

Operational definitions

are the statements of procedures (operations) used to define research variables.

Importance of Operational definitions

are important because for research to be valid it must be quantified.

Statistics

make research quantifiable.

confounding variables

other variables that could have an effect on the independent variable

random selection or sample

how subjects are chosen to participate in the experiment

placebos

fake treatments

single-blind

participant doesn't know if in control or experimental group

subject bias

tendency to act how they think they are supposed to act

double-blind

neither participant nor researcher knows the group