Variables

AQA A Level Psychology- Research Methods. Different kinds of variables and definitions with examples.

Extraneous variables

Nuisance variables that may affect the dependent variable (DV) but are not the independent variable (IV).

Examples of extraneous variables

• Age of participants

• Background noise

• Differences in memory

Confounding variables

Differences between the experimental conditions that are not part of the IV and likely to influence the DV.

Examples of confounding variables

• If all people in one condition happen to have better memories than the people in the other condition.

• If the testing material is easier in one condition than the other.

• If there are huge distractions in one condition but not the other.

Are extraneous or confounding variables a bigger problem? Why?

Confounding variables are a bigger problem than extraneous variables because they can make it appear that the IV has had an effect on the DV when really it’s the compounding variable that has.

What should you do to extraneous and confounding variables before the study starts?

Identify them at the start of the study and control them where possible.

Participant variables

Individual differences between participants that may impact the study's results.

Examples of participant variables

• Personality

• Age

• Gender

• Motivation

• Intelligence

• Concentration

Situational variables

Differences in the testing situation that may influence participant behavior or responses.

Examples of situational variables

• Background noise

• Time of day

• Temperature of room

• Weather outside the room (eg thunder)

Demand characteristics

When participants alter their behavior based on what they believe the researcher wants or doesn't want, reducing ecological validity.

Please-you effect

When a participant changes their behavior to align with what they believe the researcher wants.

Screw-you effect

When a participant changes their behavior to go against what they believe the researcher wants.

Investigator effects

Unintended influence of the researcher on the DV, often due to the experiment's design or implementation.

Standardization

Ensuring that the procedures used in the study are consistent for all variables, with the IV being the only varying factor.

Procedures are standardized by using…

• Standardized instructions read to each participant.

• Standardized equipment/ materials.

• Timings should also be standardized.

Randomization

The process of allowing every potential option to have an equal chance of occurring, without researcher bias.

Examples of randomization in a memory experiment.

• Using a random word generator to select the words you are going to use to test the participant’s memory.

• Putting everyone’s names in a hat to choose participants.

• Putting participants’ names in a hat to determine which condition they’re in.

Reliability

Refers to the consistency of research results. (If the study was replicated would it likely produce the same results?)

Validity

Refers to whether a study is truly testing what it intends to measure.