Types of experiments

• What are the four types of experiments?

  1. Laboratory

  2. Field

  3. Natural

  4. Quasi
• Define laboratory experiment

  An experiment conducted in a highly controlled environment - experimenter manipulates IV
• Give two advantages of lab experiments

  1. High internal validity (as can control extraneous variables)

  2. Replication easy
• Give two disadvantages of lab experiments

  1. Low external validity (not easy to generalise findings to real world)

  2. High chance of demand characteristics
• Define field experiments

  IV manipulated in a natural setting
• Give an advantage of field experiments

  High external validity (behaviour more likely to represent behaviour in real world)
• Give two disadvantages of field experiments

  1. Lower internal validity - more extraneous variables

  2. Can be ethical issues (no consent/privacy)
• Define natural experiments

  Change in the IV is not brought about by the researcher, but would have varied naturally, without the researcher
• Give two advantages of natural experiments

  1. Allow research that may not be possible for ethical or practical reasons

  2. High external validity (examines real life issues)
• Give two disadvantages of natural experiments

  1. Cannot demonstrate causal relationship because IV not directly manipulated

  2. Participants not randomly allocated to groups (high impact of participant variables)
• Define quasi experiments

  Where the IV is not something that varies, but is a condition that exists e.g. age, gender, level of depression etc.
• State two advantages of a quasi experiment

  1. High internal validity (as can control extraneous variables)

  2. Replication easy
• State a disadvantage of a quasi experiment

  Cannot randomly allocate participants so may be confounding variables