Types of Experiment

• What is an Experiment?

  A study that investigates cause and effect, and compares the effect of an independent variable on the dependant variable in groups receiving different levels of the independent variable.
• What are the 4 types if psychology experiments?

  • laboratory experiments
  • Field experiments
  • Quasi experiments
  • Natural experiments
• What is a Laboratory experiment?

  Where an Independent variable is manipulated in an artificial, controlled environment.
• What are the pros of laboratory experiments ?

  The experiment have high internal validity, and can establish cause and effect.
• What are the Cons of laboratory experiments?

  In artificial settings, participants' behaviour may not generalise to behaviour in everyday life. creating Low ecological validity.
• What is a Field Experiment?

  An experiment where the independent variable is manipulated in a natural, everyday life setting.
• What are the pros of a Field experiment?

  Higher ecological validity and higher external validity, because they're conducted in an everyday life setting.
• What are the cons of a Field experiment?

  Researchers have less control over extraneous variables, so the study has lower internal validity. making it harder to establish a clear cause and effect relationship.
• What is a Quasi experiment?

  an experiment where the independent variable can't be manipulated and randomly allocated to groups because it's a personal characteristic of the participants.
• What are the pros of Quasi experiments?

  Its the only way to study the effect of an independent variable that is a fixed personal characteristic of the participants.
• What are the cons of Quasi experiments?

  Participants can't be randomly allocated to groups and uncontrolled participant variables may act as confounding variables. This creates low internal validity and makes it harder to establish a cause and effect relationship.
• What is a Natural experiment?

  an experiment where the independent variable is an event that is not practical or ethical to manipulate
• What are the pros of a Natural experiment?

  It enables researchers to study independent variables that it would be unethical or impractical to investigate in a laboratory or field experiment.
• What are the cons of a Natural experiment?

  The researchers lack control over extraneous variables which reduces the internal validity making it harder to establish a cause and effect relationship.

  Very little control over extraneous variables.
• what are the ways we can allocate participants into experimental groups?

  • matched pairs design
  • independent groups
  • repeated measures
• what is Types of experimental design?

  The choice of how to allocate participants to experimental groups
• what are the two types of experiments the researcher has to a experimental design?

  Laboratory and Field experiment
• What is Matched Pair design?

  where a researcher matched the participants from the control and experimental groups for a particular participant variable
• a pro of the matched pairs design is the control over variables increase in internal validity of the study.
• the limitations of matching pairs are we cant control for ever participant variable and it can be time consuming
• What is an independent groups design?

  When the researcher allocates different participants to each group but doesn't match the participants for any particular variables.
• To control participants variables that could occur when using independent group design the researcher will usually use a random allocation procedure.
• What is a repeated measure design?

  Where the same participant takes part in all of the experimental conditions.
• what are the limitations of a repeated measures design?

  Participants have more of a chance to figure out the aim of the study meaning they may demonstrate demand characteristics.

  May be influenced by order effects which is when the order of the experimental condition influences the results of the study
• Order effects can happen if the participant becomes better at a task due to practice, and also if the participant becomes less good at a task due to boredom.
• How can you prevent order effects from influencing results of the study?

  counter balancing - different participants are made to take part in the experimental conditions in different orders
• One limitation of both independent group design and matches pair design is that the results might be influenced by participant variables.
• what happens to an experimental design in a natural or Quasi experiment?

  the researcher can't allocate participants to different levels of the independent variable, so the decision about experimental design is usually made for them.
• If researchers can't randomly allocate participants to groups, they can try to control participant variables by selecting participants that are matched for certain participle variables.
• It is unlikely that a researcher will be able to use a repeated measure design in a natural or quasi experiment.