Types of Experiments

• what is the design of a lab exp?

  • researcher is able to exert high levels of control over what happens.
  • controls the environmental factors, e.g. noise, temperature.
  • standardised procedure to ensure reliability and replicability.
  • all variables kept the same/constant (aside from IV).
  • means the DV can be measured exactly using quantitative data.
• what are the advantages of lab exps?

  • cause & effect + conclusions are more possible (due to control researcher has).
  • replicable, increases reliability (use of standardised procedure).
  • high internal validity.
• what are the disadvantages of lab exps?

  • demand characteristics may be an issue.
  • often lacks ecological validity (artificial environment).
  • can’t be generalised to reality.
• what is the design of a field exp?

  • takes place in a natural setting away from the lab.
  • researcher has less control over what happens (has to allow extraneous variables).
  • quantitative + qualitative data.
• what are the advantages of a field exp?

  • likely to have higher ecological validity as it is a real-life setting.
  • p’s are less likely to show demand characteristics.
  • high levels of mundane realism.
• what are the disadvantages of field exps?

  • harder to randomly assign, p’s more likely to change due to participant variables.
  • harder to control extraneous variables.
• what is the design of a natural exp?

  • does not manipulate the IV, uses naturally-occurring phenomena.
  • researcher has less control over what happens (can’t randomly allocate p’s.)
• what are the advantages of a natural exp?

  • allow research in areas that controlled exps could not.
  • high external vaildity (conducted in a natural setting), w/ natural behaviours being exhibited.
• what are the disadvantages of a natural exp?

  • difficult to say there is a cause & effect relationship as too many variables are uncontrolled.
  • lack of reliability, incredibly unlikely to be replicated again.
• what is the design of a quasi exp?

  • contain a naturally occurring IV.
  • the naturally occurring IV is a difference between people that already exists.
  • researcher examines the effect of this variable on the DV.
• what are the advantages of a quasi exp?

  • good for studying real-life settings for special groups (high ecological validity).
• what are the disadvantages of a quasi exp?

  • lack of control over the experimental groups used.
  • lack of random allocation.
• what is the difference between natural and quasi exps?

  • quasi = naturally occurring IV. however the naturally occurring IV is a difference between people that already exists (i.e. gender, age). researcher examines effect of this variable on the DV.
  • experimenter can’t change someone age or gender, but they could take a sample of X no. of males and females, and put them in a testable situation.
  • natural exps- experimenter cannot manipulate IV, so DV is simply measured and judged as the effect of an IV. when an event occurs and impact is measured.
  • it’s when an IV occurs naturally that the researcher couldn’t have manipulated. there’s no way to predict it or plan to study it.