Research Methods -> Experimental Methods

Question 1

Laboratory experiments

Answer 1

• Research is carried out in a controlled way.
• For an experiment to be successful, the DV and IV must be operationalised
• There may also be confounding variables which the experimenter will try and control
• The other variables than an experimenter wants to hold constant are called extraneous variables. The aim of controlling EVs is to minimise their possible impact on the results of the investigation.
• Laboratory experiments are conducted in an artificial setting

Question 2

Strengths of lab experiments

Answer 2

The effects of extraneous variables are minimised, so the experimenter can be more confident that is the independent variable which has affected the dependent variable
&
Strict controls means it is easier to replicate the study to test to reliability of findings

Question 3

Weaknesses of lab experiments

Answer 3

Lack of ecological validity because the setting is artificial, experiments may not be a reflection of real-life behaviour.
&
Demand characteristics as participants may guess the aim of the experiment

Question 4

Field Experiments

Answer 4

Behaviour is measured in a natural environment like a school or street. The independent variable is manipulated by the experimenter (i.e. participants are put into conditions) so that its effect can be measured through the dependent variable

Question 5

Strengths of field experiments

Answer 5

Field experiments are less artificial than those done in a laboratory, so they have higher ecological validity.
&
Demand characteristics can be avoided in a field study if participants aren’t aware that they’re in a study.

Question 6

Weaknesses of field experiments

Answer 6

It is harder to minimise extraneous variables in a field study, making it harder to come to a conclusion. Also less control over the sample
&
Ethics - participants who didn’t agree to take part might experience distress and can’t be debriefed. Observation must respect privacy.

Question 7

Natural experiments

Answer 7

A natural experiment is a study that measures variables that aren’t directly manipulated by the experimenter. This then means that the IV is naturally occurring.

Question 8

Strengths of natural experiments

Answer 8

High level of ecological validity because the experiment is carried out in a natural environment and the IV is not manipulated but naturally occurring, this allows for natural behaviour to be measured
&
Makes it possible to study variables that it would be unethical or impossible to manipulate

Question 9

Weaknesses of natural experiments

Answer 9

You can’t randomly allocate participants to each condition, and so extraneous variables may affect results making it very difficult to reach conclusions.
&
Some groups of interest are hard to find e.g. a community which doesn’t have TV

Question 10

Quasi-Experiment

Answer 10

This is very similar to a natural experiment in that the IV is not directly manipulated. However, Quasi experiments are generally carried out in a lab setting.

Question 11

Strengths of Quasi experiments

Answer 11

The effects of extraneous variables are minimised, so the experimenter can be more confident that is the independent variable which has affected the dependent variable.
&
Strict controls means it is easier to replicate the study to test to reliability of findings.

Question 12

Weaknesses of Quasi experiments

Answer 12

Lack of ecological validity because the setting is artificial, these experiments may not be a reflection of real-life behaviour.
&
Demand characteristics as participants may guess the aim of the experiment and alter the behaviour.

Question 13

Randomisation:

Answer 13

the use of chance in order to control for the effects of bias when designing materials and deciding the order of conditions. For example, to make sure that a list of words are not too easy or too hard, it is a good idea to put them in random order which can be done through a computer or manually.

Question 14

Standardisation:

Answer 14

Using exactly the same formalised procedures and instructions for all participants in a research study – this improves the reliability of the study

Question 15

Confounding Variables:

Answer 15

Variables that actually interfere with the measuring of the DV

Question 16

Extraneous variables:

Answer 16

these are variable that could interfere with the measuring of the IV and can be subdivided into participant variables and situational variables. Participant variables are any individual differences between participants that may affect the measuring of the DV