control of variables

• examples of situational variables


  noise

  time of study

  temperature

  instructions

  weather

  lighting
• examples of participant variables


  age

  gender

  intelligence

  concentration

  motivation

  personality

  education level
• what is a confounding variable


  any variable, other than the IV, that has affected the DV
• what are demand characteristics


  any cue from the researcher or from the research situation that may be interpreted by participants as revealing the true aims of the study

  may lead to a change in the participants behaviour

  e.g tone of voice

  micro expressions
• what is an extraneous variable


  any variable, other than the IV, that may have an effect on the DV if its not controlled

  doesn't vary systematically with the IV
• what is standardisation


  using exactly the same formalised procedures and instructions for all participants. in a research study
• what are two types of extraneous variables


  participant:

  something about the person that can affect the DV

  
  

  situational:

  something about the environment used for testing
• what is randomisation


  the use of chance to control for the effect of bias when designing materials and deciding the order of conditions

  
  

  random allocation for experimental groups
• what are investigator effects 


  any effect of the investigators behaviour on the research outcome

  
  

  e.g design of the study

  selection of participants