Placebo Effect
Experimental results caused by expectations alone; any effect on behavior caused by the administrator of an inert substance or condition, which is assumed to be an active agent.
False Consensus Effect
The tendency to overestimate the tent to which others share our beliefs and behaviors.
Experiment
A research method in which an investigator manipulates more factors (independent variable) to observe the effect on some behavior or mental process (dependent variable).
Statistical Significance
A statistical statement of how likely it is that an obtained result occurred by chance.
Theory
An explanation using an integrated set of principles that organized observations and predicts behaviors or events.
Standard Deviation
A computed measure of how much scores vary around the mean score.
Operational Definition
A statement of the procedures used to define research variables.
Ex: Human Intelligence may be operationally defined as what an intelligence test measures.
Culture
The enduring behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next.
Range
The difference between the highest and lowest scores in a distribution.
Median
Middle score of a distribution.
Mean
Average of a distribution.
Mode
The most frequently occurring score(s) in a distribution.
Dependent Variable
The outcome factor; the variable that may change in response to manipulations of the independent variable.
Independent Variable
Experimental factor that is manipulated; the variable whose effect is being studied.
Random Assignment
Assigning participants to experimental and control conditions by chance, this minimizing pre-existing differences between those assigned to the different groups.
Control Conditions
The condition of an experiment that contrasts with the experimental condition and serves as a comparison for evaluating the effect of the treatment.
Experimental Condition
The condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable.
Double-blind Procedure
An experimental procedure in which both the research participant and staff are ignorant about whether the participants have received the treatment or a placebo. Common in drug-evaluation studies.
Illusionary Correlation
The perception of a relationship where none exists.
Scatterplot
A graphed cluster of dots, each of which represents the values of two variables.
Correlation
A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.
*Correlation coefficient is the mathematical expression of the relationship; -1 to +1
Naturalistic Observation
Observing and recording behavior in naturally occurring situations without trying to manipulate or control the situation.
Random Sample
A sample that fairly represents a population because each member has an equal chance in inclusion.
Population
All the cases in a group, from which samples may be drawn for a study.
Survey
A technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them.
Case Study
An observation technique in which one person is studied in depth on the hope of revealing universal principles.
Republication
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.
Hypothesis
A testable prediction, often implied by a theory.
Critical Thinking
Thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence and assesses conclusions.
Hindsight Bias
The tendency to believe, after learning the outcome, that one would have foreseen it.
*The "I-knew-it-all-along" phenomenon.