types of experiments

• lab experiments

  Experiments are done in special, highly controlled environments.
• evaluations - lab experiments

  strength(s):

  -high levels of control = high internal validity.

  -high internal reliability - replicability possible.

  
  

  weakness(es):

  -low ecological validity - labs do not represent real life environments.

  -increased demand characteristics.
• quasi experiments

  The independent variable is based on an existing difference between people. No one manipulates the IV - it simply exists. .
• evaluations - quasi experiments

  strength(s):

  -often carried out in highly controlled environments - high internal validity.

  -experiments can be repeated.

  
  

  weakness(es):

  -there could be confounding variables.

  -hard to tell if the IV is what manipulated the DV.
• field experiments

  Researchers go to the participants environment instead of them going to the researchers environment. The IV is manipulated in a everyday setting.
• evaluations - field experiments

  strength(s):

  -high ecological validity as the research is done in the participants environment.

  -higher mundane realism than lab experiments.

  
  

  weakness(es):

  -ethical issues: informed consent.

  -hard to tell if IV manipulated DV.
• natural experiments

  The researcher has no control over the IV, they cannot manipulate it. Someone or something else causes the IV to change. The IV is natural, not always the setting.
• evaluations - natural experiments

  strength(s):

  -high ecological validity.

  -demand characteristics are less likely to occur.

  
  

  weakness(es):

  -sample could be bias - participants cannot be allocated randomly.

  -ethical issues: informed consent. Participants might not consent and there could be deception involved.
• true experiment

  IV is under direct control by the experimenter, the experimenter manipulates and records the effect the IV has on the DV