Experiments

Question 1

Definition

Answer 1

Controlled situation in which the researcher manipulates an independent variable to discover its effect on the dependent
variable, while the other variables are held constant.

Question 2

Lab Studies

Answer 2

Conducted in a well-controlled environment
Accurate measurements are possible
Researcher decides where the experiment will take place, at what time, with which participants, in what circumstances and using a standardised procedure.

Question 3

Lab Studies - Evaluation

Answer 3

Pros:
High control over extraneous variables means that they cannot confound the results, so a ‘cause and effect’ relationship between the IV and DV is often assumed.
Results of laboratory experiments tend to be reliable, as the conditions created can be replicated
Variables can be measured accurately with the tools made available in a laboratory setting
Cons:
Data collected may lack ecological validity
There is a high risk of demand characteristics, i.e. participants may alter their behaviour based on their interpretation of the purpose of the experiment.
Risk of experimenter bias, e.g. researchers’ expectations may affect how they interact with participants, altering the results

Question 4

Field Studies

Answer 4

Take place outside of the lab in a natural environment, but the basic scientific procedures are still followed as far as possible
The participants are randomly allocated as far as possible
The IV is manipulated by the experimenter
All other variables are held constant, as far as possible
The effect on the DV is measured.

Question 5

Field Studies - Evaluation

Answer 5

Pros:
Yield results with higher ecological validity than laboratory experiments, as the natural settings will relate to real life
Demand characteristics are less of an issue with field experiments than laboratory experiments
Cons:
Extraneous variables could confound results due to the reduced control experimenters have over them in non-artificial environments, which makes it difficult to find truly causal effects between independent and dependent variables
Ethical principles have to be considered, such as the lack of informed consent
Precise replication of the natural environment of field experiments is understandably difficult, so they have poor reliability
Field experiments are more susceptible to sample bias, as participants are often not randomly allocated to experimental conditions

Question 6

Natural Studies

Answer 6

Conducted in the natural environment of the participants
IV is not being changed on purpose by the experimenter
The experimenter has no control over the IV

Question 7

Quasi Studies

Answer 7

Researcher is interested in independent variables that cannot be randomly assigned
Usually this happens when the independent variable is something that is an innate characteristic of the participants involved
Quasi experiments are normally done in a lab, but don’t have to be

Question 8

Natural & Quasi Studies - Evaluation

Answer 8

Pros:
High ecological validity, as variables are naturally occurring
Cons:
Experiments have no control over the environment & other extraneous variables which means that the researcher cannot always accurately assess the effects of the I.V, so it has low internal validity
Due to the researcher’s lack of control, research procedures cannot be repeated so that the reliability of results cannot be checked