types of experiments

• what is an experiment?

  a situation where unwanted influences are controlled or removed in order to see if a change in one factor has an effect on another
• what is a laboratory experiment?

  -these studies take place under controlled conditions

  -the experimenter controls unwanted factors which may bias the results
• what are the strengths of laboratory experiments?

  1. control over extraneous variables
  2. makes the experiment replicable
• what are the weaknesses of laboratory experiments?

  1. lacks ecological validity
  2. demand characteristics- change their behaviour in order to please the researcher
• what is a field experiment?

  -takes place in a situation where that behaviour would occur normally

  -independent variable is changed
• what are the strengths of field experiments?

  1. findings can be generalised to real life meaning there is more ecological validity
  2. less demand characteristics as the participants know that they are taking part of a study
• what are the weaknesses of field experiments?

  1. extraneous variables cant be controlled because you cant control them in a real life setting
  2. lack of informed consent as participants aren't aware that they are taking part of a study
• what is a natural experiment?

  -it is not possible to manipulate the independent variable as differences occur naturally

  -they are natural because the IV would be present even if the researcher was not involved
• what are the strengths of natural experiments?

  1. ecologically valid as it is a real life setting and the experimenters cant control the study
  2. no demand characteristics as participants arent aware that they are taking part in a study
• what is a weakness of natural experiments?

  1. extraneous variables cant be controlled
• what is a quasi experiment?

  -based on existing differences between people e.g the effects of gender or age on behaviour

  -the IV cant be directly changed by the psychologist
• what is a strength of a quasi experiment?

  1. controlled to try and reduce unwanted factors
• what are the weaknesses of quasi experiments?

  1. introduces bias into the samples
  2. extraneous variables cant be controlled as the IV cant be changed directly
  3. lack of control over personal variable