variables

• what is a variable?


  a variable is anything that varies or changes within an investigation
• what is a dependent variable? 


  what is measured, any effect on the dependent variable should be caused by the change of the independent variable
• what is an independent variable? 


  what is changed (either naturally or by the researcher) so the effect on the dependent variable can be measured
• what is an extraneous variable? 


  the only thing that should influence the dependent variable is the independent variable. any other variables might potentially affect the dependent variable should be removed.

  these other additional/ unwanted variables are called extraneous variables and should be identified at the start of the research by the researcher, who should take steps to minimise their influence

  example: noise, temperature, intelligence, weather, time of day etc.
• what is a positive about an extraneous variable? 


  it has high internal validity if everything is controlled (lab experiment)
• what are participant variables? 


  they are differences between the participants ( age, gender, IQ)
• what are researcher variables? 


  they are factors such as research behaviour, appearance or gender could affect the participants response.
• what are situational variables? 


  the researcher should take control of the setting where the experiment takes place such as keeping light, sound, and temperature levels consistent
• what are the 3 types of extraneous variables? 


  participant variables

  researcher variables

  situational variables
• what is a confounding variable? 


  confounding variable are extraneous variables that have not been controlled so they have affected the study

  it is a variable that has an effect on the dependent variable

  we cannot tell if any changes to the dependent variable is due to the independent variable or the confounding variables
• what are demand characteristics? 


  this is where the participants try to work out whats going on in the experiment (aim) and change their behaviour, how they behave is no longer natural.
• how might the communication of the researcher affect the behaviour of the participant? 



  type of person the researcher is- formal or relaxed

  setting of the study

  the way the participant is approached and initially asked to volunteer

  the instructions and any implicit clues from non- verbal communication the participant may have already heard about the study
• what might the researcher do to effect the experiment? (investigator effects)


  any unwanted influence of the investigator on the outcome

  my be the way the experiment is carried out or the way it was designed (which participant is selected)

  may be conscious
• why should we consider investigator effects?


  be encouraging to one when asking for the results, be frosty to the other. give clear instructions to one, give unclear, hostile instructions to the other.
• what is randomisation?

  making as many things as possible random, to reduce investigator effects.
• what is an example of randomisation? 


  1. generate a list of words randomly
  2. decide the order of the words using a randomiser
  3. if the participant is in both conditions, then the order should be random
• what is standardisation? 


  giving all the participants the exact same environment, information and experience
• what is a single-blind procedure?


  the participant is unaware of the test being conducted. the researcher is aware of the test being conducted
• what is a negative about a single-blind procedure?


  it may be a threat to validity
• what is a positive about a single- blind procedure?

  it controls demand characteristics
• what is a double-blind procedure?


  both the participant and researcher are unaware of the test being conducted
• what is a negative about a double-blind procedure? 


  it may be a threat to validity
• how should procedures be standardised? 


  all timings should be the same

  standardised instructions read to participants