Variables
What is the independent variable (IV)
The variable manipulated by the researcher to affect the DV.
What is a posttest-only design
A design that measures the outcome only after the manipulation.
What is an order effect
When the order of conditions affects the DV.
What is a straightforward manipulation
Changing the IV directly through instructions, stimuli, or task conditions.
What are demand characteristics
Clues about the study's purpose that may influence participant behavior.
What is the dependent variable (DV)
The outcome measured by the researcher.
What is a pretest-posttest design
A design that measures the outcome before and after the manipulation.
What is a practice effect
Improved performance from experience with an earlier task.
What is a staged manipulation
Creating a planned situation or event, sometimes using a confederate, to manipulate the IV.
What is experimenter bias
When a researcher's expectations influence procedures, measurements, or results.
What is a confounding variable
A variable that varies with the IV and provides an alternative explanation for the results.
What is an independent-groups design?
Different participants take part in different experimental conditions.
What is a fatigue effect
Reduced performance because of tiredness.
Name three types of DV measures.
Self-report, behavioral, and physiological measures.
What is a double-blind procedure
A procedure in which participants and relevant researchers or assessors are unaware of the condition assignments
What is random assignment
Assigning participants to conditions by chance to reduce systematic group differences.
What is a repeated-measures design?
The same participants take part in multiple conditions.
What is a carryover effect
When an earlier treatment influences responses to a later treatment.
What is a ceiling effect
Scores are so high that further improvement cannot be detected.
What is a manipulation check
A measure that checks whether the IV manipulation worked as intended.
What is the difference between an experimental group and a control group?
The experimental group receives the treatment, while the control group serves as the comparison condition.
What is the difference between between-subjects and within-subjects designs
Between-subjects uses different participants in each condition; within-subjects uses the same participants across conditions.
What is a Latin square
A limited set of treatment orders that balances condition positions to help control order effects.
What is a floor effect
Scores are so low that meaningful differences or further declines cannot be detected.
What is a pilot study, and what is debriefing
A pilot study tests procedures on a small scale before the main study; debriefing explains relevant study details to participants afterward.