Research issues

• What is an extraneous variable?

  A nuisance variable that can be controlled and does not vary systematically with the IV
• What is a confounding variable?

  A kind of extraneous variable that varies systematically with the IV, so we cannot be sure whether the change in the DV is due to the IV or confounding variable
• What are demand characteristics?

  Any cue from the researcher that may be interpreted by ppts as revealing the purpose of an investigation, leading to the ppt changing their behaviour
• What are investigator effects?

  Any effect of the investigator's behaviour on the research outcome e.g. interaction with ppts during investigation
• What is randomisation?

  The use of chance to control the effects of bias when designing the investigation
• What is standardisation?

  Using the same formalised procedures and instructions for all ppts in a study
• How do you minimise any investigator effects?

  Randomisation

  Standardisation
• Examples of cues that the investigator may give

  Eye contact

  Non-verbal contact

  Leading questions