Variables

Question 1

Research variables

Answer 1

Research variables are factors that can change or be manipulated in a study.

Question 2

Correlational method

Answer 2

Sometimes researchers want to establish the association between 2 variables. In this case, they would use a correlational method (height - weight).

Question 3

Experimental method

Answer 3

Sometimes researchers want to establish the ‘cause and effect’ relationship between 2 variables; how one variable affects the other. In this case, they would use the experimental method (caffeine intake - lack of sleep).

Question 4

The correlational method does not require you to identify different types of variables whereas the experimental method does:

Answer 4

1. Independent variable (IV)
2. Dependent variable (DV)
3. Extraneous variable (EV)
4. Confounding variable (CV)

Question 5

Independent variable

Answer 5

The independent variable is the variable that the researcher manipulates or changes to observe its effect on the dependent variable. The different levels of the independent variable are the experimental conditions.

Question 6

Dependent variable

Answer 6

The dependent variable is the variable that the researcher measures to see how it is affected by changes in the independent variable.

Question 7

Extraneous variables

Answer 7

Extraneous variables are any variables other than the independent variable that could potentially affect the dependent variable if not controlled. They can make it harder to establish a clear cause-and-effect relationship.

For example, in a study on the effect of sleep on memory, extraneous variables could include age, intelligence, or noise levels—factors that might influence memory but are not the IV.

If these variables are not controlled, they can become confounding variables.

Question 8

Types of extraneous variables

Answer 8

1. Participant variables - age, IQ, motivation.
2. Situational variables - testing conditions, instructions given.
3. Investigator variables - age, gender, ethnicity

Question 9

Other situational variables - demand characteristics

Answer 9

Demand characteristics are cues in the environment that cause participants to change their behaviour because they believe that they have figured out the aim of the study. This can lead to participants behaving in a way they think is expected (please-you effect) or deliberately behaving in the opposite way (screw-you effect), reducing the internal validity of the study. It is mainly controlled by using a single blind technique whereby participants are unaware of the true aim or which condition they are in, reducing their ability to guess the study’s purpose.

Question 10

Other investigator variables - investigator effects

Answer 10

Investigator effects refer to any unintentional influence that the researcher has on the outcome of a study. These effects can occur through the researcher’s expectations (self-fulfilling prophecy), behaviour, tonality, facial expressions or body language, which may influence participants’ responses. This can reduce the internal validity of the study. It is mainly controlled by using a double blind technique where neither the participants nor the researcher conducting the study knows the true aim or which condition participants are in. This prevents unconscious bias from the investigator.

Question 11

Controlling extraneous variables

Answer 11

1. Participant variables - controlled by experimental design (random allocation to different conditions).
2. Situational variables - controlled by standardisation (keeping all variables constant), if repeated measures (order effect) then counterbalancing (half of participants in one condition first and then the other and vice-versa).
3. Investigator variables - random allocation of researcher if more than one.

Question 12

Confounding variables

Answer 12

Confounding variables are extraneous variables that systematically affect the dependent variable alongside the independent variable, making it difficult to determine whether the independent variable is truly responsible for changes in the dependent variable.

Unlike general extraneous variables, which may or may not influence results, confounding variables directly interfere with the cause-and-effect relationship, reducing the study’s internal validity.

For example, in a study investigating the effect of sleep on memory, if participants in the “well-rested” group are also generally younger than those in the “sleep-deprived” group, age becomes a confounding variable. It could be responsible for differences in memory rather than sleep alone.

Experimental method is aimed at preventing extraneous variables becoming confounding.

Question 13

Operationalising variables

Answer 13

Operationalising variables means defining and measuring variables in a specific, quantifiable and testable way. This ensures that the study can be replicated and that data collected is objective and reliable.

In the case of the dependent variable, operating refers to how you will measure the dependent variable. In the case of the independent variable, operating refers to how you will manipulate the independent variable.

Operationalisation is essential because abstract concepts (e.g., intelligence, stress, happiness) need to be made measurable for psychological research to be valid and meaningful.