PSY2 – Research Methods: Lesson 05

Other Types of Experiments

PSY2 RM PowerpointTeachers or students who want the original PPT please tweet @psychopepper

Learning Objectives

  • To KNOW and UNDERSTAND what the common features of all experiments are.
  • To KNOW and UNDERSTAND what the  features are of a laboratory experiment, field experiment, natural experiment and quasi experiment.
  • To EVALUATE the strengths and limitations of laboratory experiments, field experiments, natural experiments and quasi experiments.

Lesson Outline:


  1. To peer assess the answers to B and C questions on variables and hypotheses.
  2. To make rough notes on one of the four types of experiments
  3. To have taught others about this one type of experiment and to have learnt from others about the other three types.
  4. To collaborate with a group to create a puzzle piece poster of the four types of experiments from what you have learnt.
  5. To take notes in booklet on all four types of experiment.
  6. To take notes in booklet on the strengths and limitations of the use of all four types of experiments.
  7. To reflect back on the fundamental differences and similarities of all of these types.

Content Recap:

Experiment: Experiments allow us to study cause and effect (causation). They all have an IV (independent variable) and a DV (dependent variable) and make some attempt to control all other potential extraneous variables (EVs).  There are four different kinds of experiments

Laboratory Experiment: An experiment conducted in a special environment where variables can be carefully controlled. Participants are aware they are taking part in an experiment, though they may not know the true aims of the study.

Field Experiment: An experiment conducted in a natural environment for the behaviour of interest (the field) whilst still being able to have the IV and DV carefully controlled. Participants are sometimes unaware they are taking part in an experiment.

Natural Experiment: An experiment conducted in a natural environment where the variables are also naturally occurring. This is often due to practical (time, cost, effort) reasons or ethical reasons around the studying of a topic.

Quasi Experiment: An experiment conducted when it is impossible to control the independent variable.  For instance if you are studying someone’s gender ( they cannot be made into the opposite gender for the purpose of the experiment).

Control: The amount of restrictions placed.  In order to have a lot of control a research study needs to identify any potential influences on the result and make sure they are kept constant.  If this happens then we know that what we did caused the changes we see. (A positive of laboratory experiments).

ReplicationThe ability to repeat the experiment.  In order to be able to replicate a study the research had to be well designed, carried out and reported, as well as carefully controlled.  If this happened then another experimenter can ‘copy’ the research exactly. (A positive of laboratory experiments).

Ecological Validity:  The ability to repeat the experiment in a different setting (real world) and get the same results.  If we wanted to say everyone is the same then we would need to make sure that our results are true in all different settings. (A negative of laboratory experiments because they don’t have it).

Mundane Realism:  The extent to which an experiment reflects the real world.  Mundane: meaning boring, an experiment should reflect what happens in our day to day lives.  (A negative of laboratory experiments because they don’t have it).

Demand Characteristics:  A cue that makes participants aware of what the researcher expects to find, or how participants are expected to behave. They can change the outcome of a study because they can lead to changes in participants behaviour.  (A negative of laboratory experiments because they give these out).

If you would like to access PsychoPepper’s Gloassary of Terms please click here

Resources used

Jigsaw Puzzle Poster Blank

Study Notes (TBC):

If you would like to download a set of study notes for this lesson, you can do so here.  If you would like access to the original word file please tweet @psychopepper


I would suggest that you have a copy of one of the textbooks which will allow you to read around the subject matter, pre-read ahead of lessons or even take extra notes/practise questions afterwards.  I would recommend the following (you do not need to replicate books, one of each type is plenty!)

Extra ReadingElephants on Acid or Hippo Eats Dwarf


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