Variables

What is an Independent Variable?

What the researcher changes or manipulates to see how it affects something else, it’s the cause in the cause-and-effect relationship.

What is a Dependent Variable?

This is what the researcher measures — the outcome or effect, It depends on the independent variable.

What are extraneous variables?

Any unwanted variables other than the IV that could affect the DV if they’re not controlled e.g. time of day, BG noise, difficulty.

What are situational variables?

Features of a research situation that may influence participants behaviour e.g. order effects, time of day, temperature, noise, instructions given or lighting.

What are participant variables?

Any characteristics of the individual participants. This is related to individual characteristics of each participant that may impact how they respond e.g. background differences, mood, anxiety, intelligence awareness or other characteristics that are unique to each person.

What are investigator effects?

Any (unintentional) influence of the researcher’s behaviour/characteristics on participants/data/outcomes - these cues may be unconscious nonverbal cues, such as muscular tension or gestures or vocal cues like the tone of voice.

What are order effects?

Can occur in a repeated measures design, and refers to how the positioning of tasks influence the outcome e.g. practice effect (the performance in the 2nd condition may be better because the participants knows what to do) or fatigue effect (worse performance in the 2nd condition because they’re tired) or boredom effect.

Why must all other variables be kept constant in an experiment?

To ensure that any changes in the DV are caused by the IV alone, not by other factors.

What are the levels of the Independent variable?

The different conditions of the IV that are compared in an experiment, e.g. control condition vs. experimental condition.

Why are two or more levels of the IV needed?

To allow for comparison between conditions - without multiple levels, there’s no basis for comparison.

What is the control condition?

The condition where the IV is not applied or is kept at a baseline, used for comparison.

What is the experimental condition?

The condition where the IV is manipulated to test its effect on the DV.

Why must extraneous variables be controlled?

Because they can interfere with the results, reducing the study’s internal validity.

What are nuisance variables?

Extraneous variables that don’t vary systematically with the IV - they make results less clear but don’t confound them.

What are confounding variables?

Variables that vary systematically with the IV and therefore may confuse or distort the results.

What is operationalisation of variables?

Clearly defining variables in terms of how they will be measured or manipulated in a study.

Why is operationalisation important?

Because it ensures that variables are clear, measurable, and replicable for other researchers.

What is randomisation?

The use of chance methods to reduce researcher bias when designing or running an experiment.

Why is randomisation used?

To minimise investigator effects and control for extraneous variables.

Give an example of randomisation in a memory experiment.

Randomly generating the order of words in a list or the order of experimental conditions for each participant.