types of experiment

Question 1

what are laboratory experiments?

Answer 1

an experiment that takes place in a controlled environment within which the researcher manipulates the IV and records the effect on the DV, whilst maintaining strict control of extraneous variables

Question 2

what the strengths of laboratory experiments?

Answer 2

• high control over confounding (CVs) and extraneous variables (EVs)
  > the researcher can ensure than any effect on the DV is likely to be the result of the IV
  > higher internal validity ie. we can be more certain about demonstrating cause and effect
• replication is more possible than in other types of experiments due to the high level of control
  > ensures that new extraneous variables are not introduced when repeating an experiment
  > checks the results of any study to see whether the finding is valid or a one-off

Question 3

what are the limitations of laboratory experiments?

Answer 3

• may lack generalisability
  > lab environment may be artificial, so in an unfamiliar context participants may behave in unusual ways so their behaviour cannot be generalised beyond the research setting (low external validity)
• participants are usually aware they are being tested in a lab experiment which may cause ‘unnatural’ behaviour
• low mundane realism
  > the tasks participants are asked to carry out in lab experiments may not represent everyday experience

Question 4

what are field experiments?

Answer 4

an experiment that takes place in a natural setting within which the researcher manipulates the IV and records the effect on the DV

Question 5

what are the strengths of field experiments?

Answer 5

• higher mundane realism than lab experiments as environment is more natural
• may produce behaviour that is more valid and authentic, especially if ps may be unaware they are being p

Question 6

what are the limitations of field experiments?

Answer 6

• loss of control of CVs and EVs
  > means cause and effect between the IV and DV in field studies may be much more difficult to establish and precise replication is often not possible
• important ethical issues
  > if participants are unaware they are being studied they cannot consent to being studied and such research might constitute an invasion of privacy

Question 7

what are natural experiments?

Answer 7

• an experiment where the change in IV is not brought about by the researcher but would have happened even if the researcher had not been there
• researcher records the effect on a DV they have decided on

Question 8

describe the IV and DV in natural experiments

Answer 8

• IV is natural, but the setting isn’t necessarily
• DV can also be naturally occurring or devised by experimenter

Question 9

what are the strengths of natural experiments?

Answer 9

• provides opportunities for research that may not otherwise be undertaken for practical or ethical reasons
  > st helena island introduction of TV (charlton et al. 2000)
• high external validity
  > involves the study of real-world issues and problems as they happen, such as the effects of a natural disaster on stress levels

Question 10

what are the limitations of natural experiments?

Answer 10

• naturally occurring events may only happen very rarely, reducing opportunities for research
  > may limit the scope for generalising findings to other similar situations
• in an independent groups design, participants may not be randomly allocated to experimental conditions
  > researcher high be less sure whether the IV affected the DV
• research conducted in a lab may lack realism and demand characteristics may be an issue

Question 11

what are quasi experiments?

Answer 11

• experiments which have an IV based on an existing difference between people (eg. age and gender)
• no one has manipulated the IV; it simply exists
• IV also cannot be changed
• DV can be naturally occurring or may be devised by the experiment and measured in the field or lab

Question 12

what are the strengths of quasi experiments?

Answer 12

• often carried out under controlled conditions
• share some strengths with lab experiments eg. replication

Question 13

what are the limitations of quasi experiments?

Answer 13

• there may be confounding variables due to the fact that you cannot randomly allocate participants to conditions
• IV is not deliberately changed by the researcher so we cannot claim that the IV has caused any observed change