GCSEPsychologyAQARevision NotesResearch MethodsHypotheses, Variables & Research ProceduresTypes of Variables

Types of Variables (AQA GCSE Psychology)

Revision Note

Claire Neeson

Expertise

Psychology Content Creator

The independent variable

  • In psychological research, psychologists are interested in human behaviour and how it is affected and impacted by various factors, called variables
  • To study the effects of specific variables on behaviour it is necessary to change/manipulate and measure different factors 
  • The independent variable (IV) is the factor which is changed/manipulated to observe the effect it has on the dependent variable (DV), which is the variable being measured, for example:
    • whether participants learn a list of 20 words in silence or the presence of loud rock music (the IV = silence or loud rock music)
    • whether participants complete a jigsaw puzzle after 30 minutes of exercise or after no exercise (the IV = 30 minutes of exercise or no exercise)
    • whether participants have been exposed to an aggressive adult model or not (the IV = aggressive adult model or no aggressive adult model)
  • A laboratory experiment must use an IV that has been implemented by the researcher e.g. loud music or silence; the IV cannot be naturally occurring e.g. gender, age, ethnicity

Exam Tip

 As with all key terminology try not to get the independent and dependent variable confused (tricky, as they sound so annoyingly similar). One way to think about it is that the dependent variable depends on what the independent variable has done. 

The dependent variable

  • This is the factor which is measured in the study to assess the effect of the IV, for example:
    • the number of items recalled from a list of 20
    • the time taken in seconds to complete a jigsaw puzzle
    • the number of imitative acts of aggression performed in a 20-minute observation schedule
  • The DV depends on how the IV has been set up:
    • If the IV is whether participants learn/memorise something with loud music playing or in silence then it makes sense that the DV is ‘the number of….’ or ‘the time taken to…’ i.e. it must be quantitative 
  • It is impossible to have a qualitative DV:
    • The measure will always take some form of numerical data, which can then be displayed in a graph and analysed

Extraneous variables

  • Extraneous variables are any factors that intrude upon and adversely affect the DV (i.e.not the IV, which the researcher has specifically implemented). E.g.
    • time of day (some participants may be 'morning people' which means that they are likely to be more alert first thing compared to others)
    • temperature (if the experimental space is too warm/cold it may affect participant performance on the task)
    • mood (one participant may have just had a row with their partner or won some money or feel a bit ‘off’ that day: any of these events mean that their mood is likely to affect their performance on the task)

Worked example

Here is an example of a question you might be asked on this topic - for AO2.

AO2: You need to apply your knowledge and understanding, usually referring to the ‘stem’ in order to do so (the stem is the example given before the question)

Dr Winkleman has designed an experiment in which participants in one condition are told that most people lie when being interviewed by the police. Participants in the other condition are not told anything. Participants in both conditions watch the same 20-minute police interview and are asked to note down how many times they think the person being interviewed tells a lie..

Question: Identify the independent variable in this experiment.  [1]

Model answer:

  • The IV is whether participants are told that most people lie in police interviews (condition one) or are not told anything at all (condition two).

You've read 0 of your 0 free revision notes

Get unlimited access

to absolutely everything:

  • Downloadable PDFs
  • Unlimited Revision Notes
  • Topic Questions
  • Past Papers
  • Model Answers
  • Videos (Maths and Science)

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

    Next topic

    Did this page help you?

    Claire Neeson

    Author: Claire Neeson

    Claire has been teaching for 34 years, in the UK and overseas. She has taught GCSE, A-level and IB Psychology which has been a lot of fun and extremely exhausting! Claire is now a freelance Psychology teacher and content creator, producing textbooks, revision notes and (hopefully) exciting and interactive teaching materials for use in the classroom and for exam prep. Her passion (apart from Psychology of course) is roller skating and when she is not working (or watching 'Coronation Street') she can be found busting some impressive moves on her local roller rink.