Research issues

• Extraneous variables (EV)

  • Any variable, other then the IV that may affect the outcome of the DV if its NOT controlled
  • They're nuisance variables that do not vary systematically with the IV
• Extraneous variables examples

  • The lighting in the lab
  • Age of participants
  • Temperature of the room
• Confounding variable (CV)

  • A type of extraneous variable
  • That varies systematically with the IV
  • Therefore it might be hard to tell if a change in the DV is due to the IV or the CV
• Demand characteristics

  • Any cue from the researcher or from the research situation that may be interpreted by participants as revealing the purpose of the investigation
  • This might lead to them changing their behaviour in the research situation
  • It might involve them trying to please the researcher - the 'please-u-effect'
  • In might involve them tying to sabotage the results - the 'screw-u-effect'
  • These demand characteristics might as an EV and affect the DV
• Investigator effect

  • Any effect of the investigator's behaviour (conscious and unconscious) on the research outcome - the DV
  • This might include everything from the design of the study, selection of participants and interaction of with participants
  • Might include smiling more or using leading questions
• Randomisation

  • The use of chance methods to reduce the researchers unconscious biases when designing an investigation
  • Helps reduce the effects of bias, CV and EV
• Examples of how randomisation might occur

  • Memory experiment - list of words should be randomly generated
  • Order of conditions should be randomly determined
  • Counterbalancing - the order in which each these conditions were completed would need to be randomised for each patient
• Standardisation

  • Using exactly the same formalised procedures and instructions for all participants in a research study
  • This includes a standardised set of instructions