Chapter 5 - Intro to Experimental Research Flashcards
Experiment
A research procedure in which some factor is varied, all else is held constant, and some result is measured.
Independent Variables
The factor of interest to the researcher; it can be directly manipulated by the experimenter (e.g., creating different levels of anxiety in subjects), or participants can be selected by virtue of their possessing certain attributes (e.g., selecting two groups that differ in normal anxiety).
Field Experiments
An experiment conducted outside the laboratory; a narrower term than field research.
Situational Variables
Type of independent variable in which subjects encounter different environmental circumstances (e.g., large versus small rooms in a crowding study).
Task Variables
Type of independent variable in which participants are given different types of tasks to perform (e.g., mazes that differ in level of difficulty).
Instructional Variables
Type of independent variable in which participants are given different sets of instructions about how to perform (e.g., given a list of stimuli, groups might be told to process them in different ways).
Experimental Group
In a study with an identified control group, the experimental group is given the treatment being tested.
Control Group
A group not given a treatment being evaluated in a study; provides a means of comparison
Extraneous Variables
An uncontrolled factor not of interest to the researcher but that could affect the results.
Confound
An extraneous variable that covaries with the independent variable and could provide an alternative explanation of the results.
Dependent Variables
Behavior measured as the outcome of an experiment.
Ceiling Effect
Occurs when scores on two or more conditions are at or near the maximum possible for the scale being used, giving the impression that no differences exist between the conditions. - usually, task is easy
Floor Effect
Occurs when scores on two or more conditions are at or near the minimum possible for the scale being used, giving the impression that no differences exist between the conditions. - usually, task is difficult
Subject Variables
A type of independent variable that is selected rather than manipulated by the experimenter; an existing attribute of the individuals chosen for the study (e.g., gender).
Statistical Conclusion Validity
Said to exist when the researcher uses statistical analysis properly and draws the appropriate conclusions from the analysis.
External Validity
The extent to which the findings of a study generalize to other populations, other settings, and other times.
Subject Pool
Group of students asked to participate in research, typically as part of an introductory psychology course requirement; sometimes called participant pool.
Ecological Validity
Said to exist when research studies psychological phenomena in everyday situations (e.g., memory for where we put our keys).
high ecological validity it means that behaviour recorded within the research can be applied to everyday life. This means that the results are more useful.
Although test designs and findings in studies characterized by low ecological validity cannot be generalized to real-life situations, those characterized by high ecological validity can be.
Internal Validity
The extent to which a study is free from methodological flaws, especially confounding factors.
is defined as the extent to which the observed results represent the truth in the population we are studying and, thus, are not due to methodological errors.
Pretest
A measurement given to participants at the outset of a study, prior to their being treated (or not treated, if in a control group).
Posttest
A measurement given to participants at the conclusion of a study after they have experienced a treatment or been in a control group; comparisons are made with pretest scores to determine if change occurred.
History
A threat to the internal validity of a study; occurs when a historical event that could affect participants happens between the beginning of a study and its end.
Maturation
A threat to the internal validity of a study; occurs when participants change from the beginning to the end of the study simply as a result of maturational changes within them and not as a result of an independent variable.
Regression to Mean
If a score on a test is extremely high or low, a second score taken will be closer to the mean score; can be a threat to the internal validity of a study if a pretest score is extreme and the posttest score changes in the direction of the mean.
Testing
A threat to the internal validity of a study; occurs when the fact of taking a pretest influences posttest scores, perhaps by sensitizing participants to the purpose of a study.
Instrumentation
A threat to the internal validity of a study; occurs when the measuring instrument changes from pretest to posttest (e.g., because of their experience with the instrument, experimenters might use it differently from pretest to posttest).
Subject Selection Effects
A threat to the internal validity of a study; occurs when those participating in a study cannot be assigned randomly to groups; hence the groups are nonequivalent.
Attrition
A threat to the internal validity of a study; occurs when participants fail to complete a study, usually but not necessarily a longitudinal study; those finishing the study may not be equivalent to those who started it.
