Chapter 6 - Methodological Control in Experimental Research Flashcards
Between-Subject Designs
An experimental design in which different groups of participants serve in the different conditions of the study.
Equivalent Groups
Groups of participants in a between‐subjects design that are essentially equal in all ways except levels of the independent variable.
Random Assignment
The most common procedure for creating equivalent groups in a between‐subjects design; each individual volunteering for the study has an equal probability of being assigned to any of the groups
Blocked Random Assignment
A procedure used in between‐subjects designs to accomplish random assignment and ensure an equal number of participants in each condition; ensures that each condition of the study has a subject randomly assigned to it before any condition has a subject assigned to it again.
Matching
A procedure for creating equivalent groups in which participants are measured on some factor (a “matching variable”) expected to correlate with the dependent variable; groups are then formed by randomly assigning to groups participants who score at the same level on the matching variable.
Matching Variable
A variable selected for matching participants in a matched groups study.
Within Subject Design
An experimental design in which the same participants serve in each of the conditions of the study; also called a repeated‐measures design.
Order Effect
Can occur in a within‐subjects design when the experience of participating in one of the conditions of the study influences performance in subsequent conditions; see Progressive effect and Carryover effect.
Progressive Effect
In a within‐subjects design, an order effect in which the accumulated effects are assumed to be the same from trial to trial (e.g., fatigue).
Carryover Effect
Form of sequence effect in which systematic changes in performance occur as a result of completing one sequence of conditions rather than a different sequence.
Counterbalancing
For a within‐subjects variable, any procedure designed to control for sequence effects.
Complete Counterbalancing
Occurs when all possible orders of conditions are used in a within‐subjects design.
Partial Counterbalancing
Occurs when a subset of all possible orders of conditions is used in a within‐subjects design (e.g., a random sample of the population of all possible orders could be selected).
Latin Square
Form of partial counterbalancing in which each condition of the study occurs equally often in each sequential position and each condition precedes and follows each other condition exactly once.
Reverse Counterbalancing
Occurs in a within‐subjects design when participants are tested more than once per condition; subjects experience one sequence and then a second with the order reversed from the first (e.g., A–B–C–C–B–A).
Block Randomization
A procedure used in within‐subjects design as a counterbalancing procedure to ensure that when participants are tested in each condition more than once, they experience each condition once before experiencing any condition again.
Error Bars
On bar or line graphs, they indicate the amount of variability around a mean; often reflect standard deviations or confidence intervals.
Cross-Sectional Study
In developmental psychology, a design in which age is the independent variable and different groups of people are tested; each group is of a different age.
Longitudinal Study
In developmental psychology, a design in which age is the independent variable and the same group of people is tested repeatedly at different ages.
Cohort Sequential Designs
In developmental psychology research, a design that combines cross‐sectional and longitudinal designs; a new cohort is added to a study every few years and then studied periodically throughout the time course of the study.
Experimenter Bias
Occurs when an experimenter’s expectations about a study affect its outcome.
Protocols
A detailed description of the sequence of events in a research session; used by an experimenter to ensure uniformity of treatment of research participants.
Double-Blind
A control procedure designed to reduce bias; neither the participant nor the person conducting the experimental session knows which condition of the study is being tested; often used in studies evaluating drug effects.
Single Blind
A control procedure designed to reduce subject bias, in which the participant does not know which condition of the study is being tested (the experimenter, however, does know).
