types of experiments

• laboratory experiment? 


  an experiment that takes place in controlled environments within which the researcher manipulates the IV and records the effect on the DV whilst maintaining strict control of extraneous variables
• field experiments?


  an experiment that takes place in natural setting within which the researcher manipulates the IV and records the effect on the DV.
• natural experiment? 


  an experiment where the change in IV is not brought about by researcher but would've happened even if researcher hadn't been there. researcher records the effect on the DV they've decided on
• strength of lab experiments?

  have high control over confounding and extraneous variables so researcher can ensure any effect on the DV is likely to be result of manipulation of IV so high internal validity.

  replication possible cos of the high level of control so ensures that extraneous variables aren't introduced when repeating.
• limitation of lab experiments?

  lack generalisability as lab environment may be artificial and not like everyday life so low external validity

  participants aware they're being tested in lab experiment so gives rise to demand characteristics

  tasks given may not represent everyday experience so low mundane realism
• strength of field experiment?

  higher mundane realism than lab experiments as environment is more natural so produce behaviour that's more valid and authentic.

  participants unaware they're being studied so high external validity.
• limitation of field experiments?

  loss of control of EVs and CVs so cause and effect between IV and DV difficult to establish and precise replication not possible

  ethical issues as participants unaware they're being studied so can't give consent
• strength of natural experiment?

  provide opportunities for research that may not be undertaken for practical or ethical reasons

  often have high external validity as involve the study of real world issues and problems.
• limitation of natural experiment?

  naturally occurring event happens rarely reducing opportunities for research so limits scope for generalising findings to similar situations.

  participants not randomly allocated to experimental conditions so researcher less sure whether IV affected DV
• quasi experiment? 


  experiment that has an IV based on an existing difference such as age or gender. no one manipulates this variable, simply exists and can't be changed. DV may be naturally occurring
• strength of quasi experiment?

  carried out under controlled conditions so replication more possible and has high internal validity
• limitation of quasi experiment?

  can't randomly allocate participants to conditions so may have confounding variables.

  IV isn't deliberately changed by researcher so can't claim the IV has caused any observed change