Unit 3 Flashcards
An indication of accuracy in terms of the extent to which a research conclusion corresponds with reality. The researchers conclusion is true or correct, it corresponds to the actual state of the world
Validity
Error that occurs when the effects of two variables in an experiment cannot be separated, resulting in a confused interpretation of the results
Confounding
The difference between subjects that cannot be controlled but can only be selected
Subject variable.
The problem of confounding is particularly acute in research in which the experimenter cannot control the independent variable, when participants are selected according to the presence or absence of a condition and not selected simply to have a condition assigned to them
The extent to which the results support the theory behind the research. Can you generalize from the specific operations of your experiment to the general theoretical construct about the population in question?
Construct validity
Describe the several ways to determine if a test has construct validity
Use a manipulation check, an aspect of an experiment designed to make certain that variables have changed in the way that was intended.
You must rule out other possible theoretical explanations of the results, you may have to perform another study to rule out a threat to validity. In the case of construct validity, you must design a new study that will permit a choice between the two competing theoretical explanations of the results
How well the findings of an experiment generalized to other situations or populations
External validity
Extent to which data are shown to be the result of cause-and-effect relationships rather than accident
Statistical conclusion validity
To establish statistical conclusion validity, appropriate sampling in measurement techniques must be used, and inferential statistics must be used properly, in keeping with their underlying assumptions
Briefly describe the major threats to internal validity
Ambiguous temporal precedence, events outside the laboratory, maturation, effects of testing, regression effect, selection, mortality
A threat to internal validity. Although two variables are related, it is not clear which one is the cause and which one is the effect
Ambiguous temporal precedence
A threat to internal validity. Events that occur outside of the experiment that could influence the results of the experiment.
History. For example, different experimental conditions are presented to subjects at different times.
A threat to internal validity. A source of error in an experiment related to the amount of time between measurements
Maturation
A threat to internal validity where performance on a second test is influenced by simply having taken a first test
Effect of repeat testing
A threat to internal validity. The tendency of subjects with extreme scores on a first measure to score closer to the mean on a second testing
Regression effect
A threat to internal validity. That part of the value of a variable that can be attributed to chance
Random error
A threat to internal validity. A confound that can occur due to assignment of subjects to groups
Selection
A threat to internal validity. Dropping out of some subjects before an experiment is completed, causing a threat to validity
Mortality
Briefly describe to threats to construct validity
A loose connection between theory and method. poor measure of the theoretical constructs and suffers from poor operational definitions of theoretical constructs
An ambiguous effect of independent variables. When results are compromised because the participants perceive the situation differently than the experimenter does. Because some participants may see the situation in the same way as experimenter, but others understand it differently, experimental circumstances are ambiguous and the independent variable may be affected differently in the participants
Briefly describe three threats to external validity
Other subjects. A common indictment of psychological research is that it uses mainly college students and white rats experimental subjects due to their accessibility and presumed representativeness. The problem is that millions of species of animals exist, most of them insects. We cannot assume that any animal can be substituted for any other in all situations. Human participant should be chosen with equal attention to the representativeness relative to some larger population.
Other times. The same experiment conducted at another time may not produce the same results due to the culture and attitudes at the time.
Other settings. How will the phenomenon observed in one laboratory be related to a similar phenomenon observed in another laboratory or in the real world? Though laboratory research ensures a higher level of control, it is sometimes not easy to decide if a certain effect is simply a laboratory effect or whether it would survive transplantation to the world outside
What are the two broad categories of bias resulting from the interaction between subject and experimenter?
Role demands and experimenter bias
Participants’ expectations of what an experiment requires them to do
Role demands
Tendency of experimental participants to act according to what they think the experimenter wants
The good subject tendency
Tendency of experimental participants to alter their behavior to appear as socially desirable as possible
Evaluation apprehension
How might role demands be overcome?
Deceive the subject about the experiments purpose. Divide the experiment in such a way that part of the data are obtained in another setting which makes it less likely that participants will put two and two together and surmise the hypothesis.
Use a measure that is unlikely to be influenced by participants guesses about the hypothesis
When an experimenter unintentionally biases the results of an experiment
Experimenter bias
How might experimenter bias be overcome?
Have the experimenter be blind to the condition a subject experiences
Standardize or automate experiments as much as possible
Any means used to rule out threats to the validity of research
Control
How is the concept of control used in psychology?
As a standard of comparison, and as a way of reducing variability
Subjects in an experiment who receive treatment
Experimental group
Subjects in a between subjects design experiment who are like the experimental group in every respect except that they do not receive treatment
Control group
A condition in a within subjects design experiment that does not contain the experimental manipulation
Control condition
Research design in which each subject experiences every condition of the experiment
Within subjects experiment
Research design in which each subject experiences only one of the conditions in the experiment
Between subjects experiment
What are the meanings of control experiment and experimental control
The primary meaning of control, control experiment, allows one to conclude that a dependent variable is associated with an independent variable and not with any other variable.
The second usage, experimental control, facilitates drawing this conclusion by so limiting the number of variables operating in the situation in the range of values that the conclusion is clear. When we have experimental control we have a much more sensitive situation in which to rule out alternative explanations of the experimental results.
Both meaning to the term control relate to the use of statistics in research. First, we use inferential statistics to evaluate the probability that a difference between experimental and control groups or conditions is likely to have arisen by chance alone. Second, we make enough observations or use enough subjects to reduce the variability of our estimate of the size of experimental effect, and so make our statistical evaluation more precise.
What are three general strategies for achieving control in psychological research?
Using a laboratory setting, considering the research setting as a preparation, and instrumenting the response
The research setting as a preparation is a strategy for achieving control. Describe it.
A preparation is an environment that is selected are constructed for a particular purpose. Everything that is part of the research setting is a part of the preparation, which is really a context for data collection. So the preparation includes experimental equipment, the method of testing, and the location of testing, as well as the subject used in the study. You need to decide which situation will provide the most powerful relationship between the variables of interest
Instrumentation of the response as control is a strategy for achieving control. Describe it
It is a way to him prove the measurement of the behavior being studied. The precision with which you measure the dependent variable can influence the results. The term instrumentation is a task of improving response measurement, it calls attention to measurement devices as instruments reducing behavior to forms convenient for data analysis, such as numbers. One characteristic of a good measurement instrument is that it takes a response out of the realm of casual observation and makes it reliable, giving accurate measurements time after time
A powerful control technique in which each participant experiences every condition of the experiment. In this way, variation caused by differences between people is greatly reduced.
Subject as own control or within subjects control
What are the limitations of having the subject as it own control
It is not possible in some situations. For example, once the participant has learned something by one method, learning the same problem again by using a different method is impossible.
Another situation where it is not possible occurs when contrast effect exist between the conditions of the experiment, so that experiencing one condition may carryover and influence the response to another condition. Also known as order and sequence effects
Unbiased assignment process that gives each subject and equal an independent chance of being placed in every condition
Random assignment
A control procedure to ensure that experimental and control groups are equated on one or more variables before the experiment
Matching
How can random assignment be performed?
You can assign numbers to individuals, and use a random number table.
Use a computer generated randomization program
Control procedure to ensure that experimental and control groups are equated on one or more variables before the experiment
Matching
When is matching necessary?
When the subjects different mind them selves on an independent variable known or suspected to affect the dependent variable of interest
What is the proper matching procedure?
You must first justify that there is a strong suspicion that there is an important variable in which the subjects differ that can be controlled and you must believe that a substantial correlation will be present between the matching variable and the dependent variable.
You would have to present a pretest to the subjects before signing them to the conditions and then pair off similar subjects into different groups using a randomized procedure
First you would minister the pretest, you then rank subjects on pretest, then form pairs on the basis of ranking, and then randomly assigned members of pairs to groups. Youth minister the experimental treatments and examine the differences between the members of pairs
A condition in an experiment that cannot easily be removed and so is made an independent variable as a means of control
Nuisance variable.
Nuisance variables are known or suspected to affect the Inpendant variable, but variables in which you have no theoretical interest. Left uncontrolled, these variables may affect the dependent variable so strongly that they hide the true effects of the independent variable. Building these nuisance variables into your study allows you to measure their effects and to examine the effects of your independent variable.
For example your participants include both day school and night school students which may affect the dependent variable due to their characteristics. You can either choose to only Study the day students or you can build it in to the experiment
Mathematical means of comparing subjects on paper when they cannot be equated as they exist in fact
Statistical control
Repeating an experiment to see if the results will be the same
Replication
This type of replication occurs when someone repeats essentially the identical experiment in an attempt to obtain the same results
Direct replication.
Seldomly carried out because finding exactly the same thing as someone else did brings little glory and it is difficult to get grants and to get published. Attempted only when systematic replication has failed
With this type of replication, researcher B will do an experiment similar to researcher A’s but with different types of subjects, with different values of the stimulus, or with different ways of measuring the theoretical concepts.
Systematic replication
Extent to which a study provides evidence of a cause-and-effect relationship between independent and dependant variable’s. It really was the independent variable that cause the dependant variable to change
Internal validity
