practical issues

• Practical decisions/implications (AO1 INTRO)

  • Balance different possibilities when designing studies with effects on reliability and validity of data
  • Implications of experimental design, sampling and data collection on research findings
• types of experimental design

  1. independent groups design

  2. repeated measures design

  3. matched pairs design
• independent groups design - Loftus & Palmer (AO3)

  • investigated effect of leading questions on recall of car crash - used IG design as RM would have made it easy for participants to guess the aim of the study
• Independent groups design - limitation

  Introduce possibility of participant variables affecting results
• Repeated measures designs

  Increase effect of extraneous variables
• strength of matched pairs design (AO3)

  • Counteract issues of independent groups and repeated measures designs
  • e.g. ppts matched for age and level of education in Gaurdia’s study
• matched pairs - Gaurdia (AO3)

  • study on perception of researcher fitting through doorway - used MP because if they used unmatched pairs, they may have interpreted the researcher’s ability to walk through the doorway differently
• types of sampling (AO1/3)

  • Random sampling least biased but not easy
  • Opportunity sampling more straightforward but may not get right participants
  • Volunteer sampling preferable for specific phobias
• volunteer sampling - Capafons (AO3)

  • investigated systematic desensitisation for fear of flying - used VS as it ensured all participants had a genuine phobia of flying
• limitation of volunteer sampling in Capafons (AO3)

  they may have been more invested in curing fear (hence volunteering), reducing validity of findings
• Data collection

  1. Decide on overt or covert observation

  2. Prepare data for analysis
• covert observation - Bandura (AO3)

  • study on children modeling adult behaviour
• covert observation limitation (AO3)

  Researchers may miss some elements of behaviour
• Covert observation with participant observation

  • Sherif's Robbers Cave study
• Validity

  • Internal validity - avoiding confounding variables
  • External validity - representing real behaviour
• data collection implications (AO1)

  1. Deciding whether an observation will be overt or covert

  2. How the researcher positions themselves

  3. How they would take notes

  4. Preparing the data for analysis

  5. How the analysis will take place

  6. Whether you can use interferential testing

  7. How you can display the data
• covert observation - Bandura (AO3)


  • the children did not know they were being observed
  • Researchers observed behaviour through a one way mirror - provided good view of children’s behaviour and them to easily see extent to which they modelled the behaviour
• limitation of covert observations (AO3)


  Researchers can miss some elements of the behaviour they are observing as they cannot move into a better position to view it
• covert observation - Sherif (AO3)


  • Involved covert observation but using a participant observation design whereby the camp supervisors who were recording the behaviour were part of the study itself
  • Enabled the supervisors to observe behaviour from within the study therefore maximising the accuracy of their observations
• What is internal validity? (AO1)


  How well an experiment avoids confounding variables ie more than one possible independent variable [cause] acting at the same time
• internal validity - loftus & palmer (AO3)


  • Designed to maintain internal validity as it clearly isolates the IV (the verb) in order to precisely measure its effects on the DV (their estimate of car’s speed)
  • Showed that the changing verb did change the participants estimates of speed
• limitation of high internal validity (AO3)


  may reduce its external validity
• what is external validity? (AO1)


  Whether the findings represent real behaviour or not (ecological validity)
• external validity - Valentine & Mesout (AO3)

  • Investigated the effect of stress on recall by using the realistic setting of the London dungeons
• It is important for researchers to consider issues of validity when designing research as focusing on different types of validity will produce different types of research with different outcomes