experimental methods + research issues

• aim:

  • identify exactly what they intend to research
• hypothesis:

  • makes a prediction of what they think their research will show
• alternative hypothesis:

  • predicts something other chance has caused results
• null hypothesis:

  • results can be experienced by chance alone
• directional hypothesis:

  • direction in which results are expected
• non directional hypothesis:

  • doesn't predict a direction in which results are expected
  • used if theres no previous research or contradictory studies
• independent variable:

  • variable that is changed, manipulated IV has a direct effect on the DV
• dependant variable:

  • variable that is measured
• operationalisation:

  • hypothesis should contain an operationalised IV and DV - clearly defined, measurable
• extraneous variables:

  • effects 2 groups
  • any variable apart from IV that may have an effect on DV if not controlled
• confounding variables:

  • effects 1 group
  • vary systematically and is directly related to the IV
  • could affect the DV alone, not because of DV
• demand characteristics:

  • work out whats going on or interpret certain cues
  • change their behaviour, in expected way or underperform to sabotage
  • single and double blind trials can decrease dc
• investigator effects:

  • unwanted influence of the investigator on research outcome - expectancy effects or unconscious cues e.g smiling
  • actions - selection, materials,instructions
  • double blind, randomisation and standardisation decrease effects
• randomisation:

  • use of chance methods to control effects of bias
  • presenting materials randomly - number generator
  • when participants involved in >1 condition - order of conditions should be randomly determined
• standardisation:

  • using exactly the same formalised procedures and instructions for all participants