experiments

• lab experiments 


  experiment that takes place in a controlled environment where the experimenter manipulates the IV and measures the DV

  1. Standardised instructions- The instructions given to each participant are kept identical – to help prevent experimenter bias.
  2. Standardised procedures- In every step of the research all the participants are treated in exactly the same way and so all have the same experience.
• evaluation of lab experiments 


  • easier to replicate a laboratory experiment. This is because a standardized procedure is used.
  • They allow for precise control of extraneous and independent variables. This allows a cause and effect relationship to be established.
  • The artificiality of the setting may produce unnatural behavior that does not reflect real life, i.e. low ecological validity. This means it would not be possible to generalize the findings to a real life setting.
  • Demand characteristics or experimenter effects may bias the results and become confounding variables.
• field experiment 


  experiment that takes place in a natural setting where the experimenter manipulates the IV and measures the DV
• evaluation of field experiment 


  • Behavior in a field experiment is more likely to reflect real life because of its natural setting, i.e. higher ecological validity than a lab experiment.
  • There is less likelihood of demand characteristics affecting the results, as participants may not know they are being studied. This occurs when the study is covert.
  • There is less control over extraneous variables that might bias the results. This makes it difficult for another researcher to replicate the study in exactly the same way.
• natural experiment 


  These are conducted in the everyday (i.e. real life) environment of the participants, but here the experimenter has no control over the IV as it occurs naturally in real life
• evaluation of natural experiment 


  • Behavior more likely to reflect real life because of its natural setting, i.e. very high ecological validity.
  • There is less likelihood of demand characteristics affecting the results, participants may not know they are being studied.
  • Can be used in situations in which it would be ethically unacceptable to manipulate the independent variable,
  • may be more expensive and time consuming than lab experiments.
  • no control over extraneous variables that might bias the results. makes it difficult for another researcher to replicate the study in exact same way.
• quasi experiments 


  those where the change in IV cannot be manipulated or randomly assigned (i.e: male/female, young/old).
• evaluation of quasi 


  • Due to the IV naturally occurring within the individual it may be more reflective to that individual.
  • They allow researchers to investigate variables that would be unethical to manipulate
  • Control over extraneous variables is often difficult. As the researcher is not manipulating the IV, they can be less sure that it caused an EFFECT on the DV.
  • They are generally hard to replicate and therefore can lack internal and external reliability.