Research Methods

• What is the purpose of research?


  To test psychology theories and for support
• What do psychologist do

  They try to explain human behaviour
• Psychologists develop

  theories and have to work out ways to test their theories, this is why research is needed
• Lab experiments...


  are ones that are conducted in a highly controlled, sometimes artificial environment
• Lab experiments do not

  always happen in a laboratory eg in a classroom
• In a lab experiment, the researcher decides

  Where it happens, when it happens, who participates, what they do and control what to control eg situational factors like temp.
• In a lab experiment, there is an

  independent (the cause) and dependant (the effect) measured
• Psychologists carry out lab experiments on


  humans called participants
• Field experiments is

  carried out in an natural environment
• Field experiments IVs are

  still manipulated but is done in an environment which is typical to the behaviour being studies
• In field experiments,


  participants are not aware they are being studied
• Natural experiments are carried out

  in a natural environment or a lab.
• Natural experiments IVs


  are not directly manipulated instead it is naturally occuring
• In Natural experiments researchers

  take advantage of changes to investigate
• Quasi experiments are carried out

  in a natural environment or a lab
• Quasi IVs are


  not manipulated, it simply exists
• Quasi IVs are


  based on existing differences between people
• Lab experiments summary

  Controlled. IV manipulated. Participants aware
• Field experiment summary

  Natural environment. IV manipulated. Participants not aware.
• Natural experiment summary


  Natural or Lab. IV naturally occurring.
• Quasi experiment summary

  Lab or natural. IV is based on existing differences
• Evaluating methods


  need to think about what practical, theoretical, or ethical issues may arise when using these methods.
• Evaluating methods - practical

  time, costs etc
• Evaluating methods - ethical

  informed consent, confidentiality, right to withdraw etc
• Evaluating methods - Theoretical

  Validity, reliability
• Internal Reliability is 


  a measure of consistency within itself, such as whether the different questions in a questionnaire are all measuring the same thing
• External reliability is

  assuring consistency when different measures of the same thing are compared. Can be improved using standardised procedures
• Internal Validity is

  extent to which the observed effect was due to experimental manipulation (what you are studying) rather than other factors
• External validity is


  the extent to which research findings can be generalised beyond research; to other settings and over time
• Lab experiments strengths

  Well controlled. Extraneous Variables minimised, thus higher internal validity. Can be easily replicated, demonstrating external validity
• Lab experiment weaknesses

  Artificial, a contrived situation- participants may know they're being studied, materials may lack mundane realism. environment unfamiliar. Therefore participants ay not behave naturally leading to ecological validity.
• Field experiment strengths

  Less artificial, usually higher ecological validity. Usually higher mundane validity. Participants not aware they be studied.
• Field experiment weaknesses

  Less control of extraneous variables, reduces internal validity. More time consuming and expensive.
• Natural experiment strengths 


  Allows research where IV can't be manipulated for ethical or practical reasons. Enables psychologist to study real problems such as the effects of disaster on health.
• Natural experiments weaknesses

  Cannot demonstrate casual relationships because IV not directly manipulated. Random allocation not possible, therefore there may be confounding variables that cannot be controlled, a threat to internal validity.
• Quasi experiment strengths

  Allows comparison between types of people.
• Quasi experiments weaknesses

  Can only be used where conditions vary naturally. Participants may be aware of being studied, thus reducing internal validity. DV may be a fairly artificial task, reducing ecological validity.