EXPERIMENTAL METHOD

• Experimental Method


  A research method in which the researcher is able to exert high levels of control over what happens as part of the experimental process
• Laboratory Experiments


  • The researcher controls the environmental factors, such as noise and temperature (possible extraneous variables) so that the effects of the independent variable (IV) upon the dependent variable (DV) can be clearly observed and measured
  • Use a standardised procedure to ensure replicability and reliability
• Lab experiments use a standardised procedure to ensure replicability and reliability
• Standardised procedure in lab experiments

  • The same number of participants take part in each condition of the IV
  • Each participant is given the same instructions (apart from instructions regarding the task as this will differ per condition as per the IV)
  • The same task/materials are used as far as is possible given the IV
  • Participants are given the same amount of time to complete the task per condition and across conditions if the IV allows it
  • All variables are kept the same/constant: only the independent variable changes between conditions
• Quantitative data


  Data that can be measured and expressed numerically
• Strengths of Lab Experiments

  • Cause and effect conclusions are more possible than other methods due to the control the researcher is able to exert
  • The use of a standardised procedure means that the research is replicable which increases reliability
  • High internal validity is achieved as the independent variable may be seen to affect the dependent variable without interference from extraneous variables
• Limitations of Lab Experiments

  • Demand characteristics may be an issue as participants know they are in a study and so may alter their behaviour which impairs the validity of the study
  • Often lacks ecological validity due to the artificial nature of the procedure
  • Often lacks mundane realism meaning the results cannot be generalised to real-world behaviour
• Field Experiments


  A research method which takes place in a natural setting, away from the lab
• Field Experiments


  • The researcher has less control over what happens as part of the experimental process
  • The researcher controls the environment to some extent but they have to allow the fact that many extraneous variables are included in field experiments
• Field experiments still involve the implementation of an IV and DV
• Qualitative data


  Data that is descriptive and cannot be expressed numerically
• Field experiments collect quantitative data but there is also more scope for researchers to obtain qualitative data as part of the research process
• Any qualitative data collected could be used to comment on the quantitative findings and shed light on the actions of the participants
• Strengths of Field Experiments

  • Likely to have higher ecological validity as it is a real life setting
  • Participants are less likely to show demand characteristics as they are less likely to know what is expected from them and are often in their 'natural' environment
  • High levels of mundane realism, which means the results are more likely to be able to be generalised to real-world behaviours
• Limitations of Field Experiments

  • Harder to randomly assign participants and so means it is more likely a change could happen due to participant variables, rather than what the researcher is measuring
  • Harder to control extraneous variables within the experiment, which could change the measurement of the dependent variable
• Natural Experiments


  A research method which does not manipulate the IV, it uses naturally-occurring phenomena
• The researcher has less control over what happens as part of the experimental process as they cannot randomly allocate participants to condition (the participants are the conditions e.g. either young/old, trained/untrained)
• Natural experiments collect quantitative data
• Strengths of Natural Experiments

  • Allow research in areas that controlled experiments could not conduct research, this could be due to ethical or cost reasons
  • High external validity as they are conducted in a natural setting with natural behaviours being exhibited
• Limitations of Natural Experiments

  • Difficult to say there is a cause and effect relationship as too many variables are unable to be controlled so could effect the outcome
  • Lack of reliability as incredibly unlikely to be able to replicate the same situation again to test