Research Methods (Exam 2)

What is an independent variable?

It is the factor of interest to the experimenter, the one being studied to see if it will influence behavior. It is sometimes called a manipulated variable or factor because the experimenter has complete control over it and is creating the situations research participants will encounter in the study

What is a dependent variable?

Used to describe the behavior that is measured the behavior that is measured outcome of a study

What are the different types of IVs?

• Situational

• Task

• Instructional

Situational IV

Features in the environment that participants might encounter

Task IV

give participants different kinds of problems to solve

Instructional

Manipulated by telling different groups to perform a particular task in different ways

What is the purpose of a control group?

It is a group not given a treatment being evaluated in a study; it provides a means of comparison. Provides a baseline measure against which the experimental group’s behavior can be compared.

When do we not use a control group?

When there is a comparison between two different types of treatments, one may not require a baseline, and studies involving subject variables (like comparing males to females) do not typically use a control group in the same sense

Why might some ethicists critique the use of control groups?

Some argue that assigning participants to a control group may be unethical if it involves withholding a potentially beneficial treatment. In medical or psychological research, this can lead to feelings of rejection or added stress for control participants, which might negatively affect their health

What is an extraneous variable?

Any uncontrolled factor that is not of primary interest to the researcher but could potentially affect the results

What is a confounding variable?

An extraneous variable that covaries with the independent variable, providing an alternative explanation for the study’s outcomes

What problems are caused by confounds?

Confounds make the results of a study uninterpretable because there is no way to determine if the outcome was caused by the IV, the confound, or a combination of both

How do we avoid confounds?

Researchers avoid them by holding extraneous variables constant across all conditions and using procedures like random assignment, matching, or counterbalancing to ensure group equivalence and control for order effects

What is the difference between a “subject” and “manipulated” IV?

A manipulated IV, the encounter has total control over the factor and creates the conditions participants experience

A subjective IV, the experimenter cannot manipulate the trait but instead selects participants based on characteristics they already posssess

Advantages of IVs

They allow for the study of variables that would be unethical or impossible to manipulate, such as brain damage, cultural background, or personality disorders

Disadvantages of IVs

Causal conclusions cannot be drawn. Because participants are not randomly assigned, groups may differ in numerous uncontrolled ways, making it impossible to rule out alternative explanations

What is internal validity? How can we increase it?

The degree to which a study is methodologically sound and free from confounds, ensuring that the results are directly attribute to the IV. It can be increased by using control groups, random assignment, matching, and counterbalancing

What is external validity? How can we increase it?

The degree to which research findings generalize beyond the specific context of the experiment to other populations, environments, and times. It can be increased by using diverse participant samples and natural settings and through replication

What is the relationship between internal and external validity?

These two forms of validity often exist in a tug of war. Rigidly controlled laboratory settings (high internal validity) may feel artificial and lack mundane realism (low external validity), while natural settings (high external extraneous variables (low internal validity)

What are some common threats to internal validity?

• History: external events occurring during a study that might influence the outcomes

• Maturation: biological or psychological changes in participants due to the passage of time

• Regression to the mean: the tendency for extreme scores on a pretest to move toward the average upon a second measurement

• Subject selection: a problem occurring when participants in different groups are not equivalent at the start of the study

• Attrition: participants dropping out of the study before its completion, which can systematically bias at the final sample

• Order Effects: in within-subjects designs, performance may be affected by the sequence of conditions (e.g, fatigue, practices, or carryover effects)