Experiments Flashcards
What is the purpose of an experiment
To establish a cause and effect relationship between two variables
What are the 3 types of varbiles that you should consider
-independent variable
-dependent variables
-extraneous variables
What is a independent variable
It’s manipulated by the researcher. We can identify it as it creates different conditions
What is the dependent variable
It’s the variable that is measured. The do and in will be measured the same way in all iv conditions
What is the extraneous variable
If it isn’t controlled then it can effect the results
How do you operationalise the independent variable
Knowing precisely how the variable was manipulated and stating the conditions
How do you operationalise the dependent variable
Measure it accurately and give the units used
What are control conditions
Is where no manipulations have been made and is usually used to gain a baseline measure
What is an experimental condition
A condition where the IV has been manipulated to suggest a cause and effect
What are the 3 types of experimental methods
-lab experiments
-field experiments
-quasi experiment
What is a lab experiment
An experiment that is conducted in a highly controlled environment which is artificial. The researcher directly manipulates the IV while keeping any other factors under close control. This allows them to observe a change in do as a direct cause of the IV
What is a field experiment
It is conducted in a natural environment. The IV is still manipulated but in a naturally occurring environment. The participants are unaware that the study is taking place
What is a quasi experiment
The researcher makes use of an existing IV and therefore doesn’t manipulate the IV. Research can’t randomly assign participants to a condition
What are the strengths of a lab experiment
- high levels of control mean there are no extraneous variables. Therefore clear cause and effect relationship between iv and even can be found
- high levels of controlling also mean the study can be easily manipulated, increasing internal reliability
What are the weaknesses of a lab experiment
-artificial setting bears little resemblance to real life. Therefor lacking ecological validity meaning the findings can’t be generalised
-participant are brought into a lab experiment purposefully which could lead to demand characteristics or evaluation apprehension. Decreasing internal validity
What are the strengths of field experiments
- likely to get behaviours which resemble real life and therefore can be generalised and this leads to high ecological validity
- low chance of demand characteristics. Therefore increased ability to determine cause and effect and suggesting high internal validity
What is a weakness of field experiments
- low levels of control means lots of extraneous variables. This means that cause and effect is difficult to establish reducing internal validity
- difficult to replicate so can’t confirm that findings are reliable
What is the strengths of quasi experiment
- the researcher can use a IV that would otherwise be unethical to manipulate . This allows use to gather more insight which leads to develop practical applications
- often done in a lab environment which allows high control over extraneous variables. Therefore you are able to determine the cause and effect
What are the weaknesses of a quasi experiment
- the if is naturally occurring as participants will naturally belong to one condition or another. Therefore research can’t randomly allocate conditions to people.
- some Ivs are not frequently occurring. Therefore it can take time to fully test the effects of something
What are the three types of experimental designs.
D stand for divide the participants
- independent measures
- repeated measures
- matched pairs /participants
What are independent measures
Participants are randomly allocated one of the experimental conditions
What is the strength of independent measures
No risk of order effect
What is the weakness of independent measures
- high risk of individual measures
- inefficient use of participants as each person is only used once
What are repeated measures
Participants take part in all the experimental conditions