Experimental Method Flashcards
What are the 4 types of experiments?
- Laboratory
- Field
- Natural
- Quasi
Independent Variable
- What the researcher manipulates.
- Assumed the IV will have a direct effect on the DV
Dependent Variable
- What the researcher measures (the change in behaviour)
- Look at how behaviours change as a result of the manipulation of the IV.
Extraneous Variables
- Any variables other than the IV that might affect the DV
Confounding Variables
- Extraneous variables that cannot be controlled
2 advantages of the Experimental method
- Easy to replicate due to the high level of control
> Others can carry out the experiment to check the reliability of the results - Causal relationships can be inferred
> Changes in dependent variable are due to changes in the independent variable.
2 disadvantages of Experimental method
- Low Ecological validity
> Findings cannot be generalised to real life situations - Demand Characteristics
> Change behaviour if they know the aim of the study
Operationalise
- Operationalisation means to ‘make testable’.
- We operationalise our IV and DV in order to make it testable
Laboratory Experiments
- Scientific method
> Highest level of control over all variables
2 advantages of Laboratory experiments
- Easy to replicate
> Easy to test the reliability of the original findings. - High degree of control
> Easy to assume that changes in the DV are due to changes in the IV.
2 disadvantages of Laboratory experiments
- Low Ecological Validity
> Difficult to generalise the findings to real world situations (Artificial study) - Demand characteristics
> Participants may change their behaviour
Field Experiments
- Carried out in the participants’ natural environment
> Measuring behaviour in the location in which it would normally occur.
2 advantages of Field experiments
- High ecological validity
> Conducted in the participants’ own environment (participants are acting as they normally would) - Less chance of demand characteristics
> Often unaware they are taking part in a study (unlikely to change their behaviours)
2 disadvantages of Field experiments
- Less control Researchers
> Cause and effect relationship between IV and the DV is not as strong - Potential ethical issues
> Participants don’t know that they are taking part in the study
Natural Experiments
- IV is not directly manipulated by the researcher
- Naturally occurring
2 advantages of Natural experiments
- High ecological validity
> Participants acting naturally, happens to be researchers to measure their behaviours. - It allows the study of sensitive issues
> Involve an IV that would be unethical to manipulate
2 disadvantages of Natural experiments
- Difficult to replicate
> Changes in the IV are ‘one offs’- reliability cannot be tested through replication. - Lack of control
> IV is not being directly manipulated by the researchers
Quasi Experiment
- IV which forms part of the participant
> (e.g. their age, gender or personality type) - Participants cannot be randomly allocated to conditions
2 advantages of Quasi experiments
- High degree of control
> Carried out in the same controlled conditions as laboratory experiments - Replicable
> When the IV is straightforward easy to repeat the study
2 disadvantages of Quasi experiments
- Random allocation to conditions not possible
> This means that by chance the two conditions could differ on a variable that might affect the DV - Difficult to find a sample if condition of the IV is rare
> Hard to recruit the required number
What are the 2 types of extraneous variables?
- Situational Variables
- Participant Variables
Situational Variables
- Variables connected with the research situation
> eg. temperature, instructions, time of day, lighting and materials used in the investigation are all situational variables. - Controlled through standardisation
> Ensuring that the only thing that differs between the two conditions is the IV - Standardised instructions - ‘set instructions’ that should be read to all participants
- Standardised procedures - Detailed instructions as to how the research should be carried ou
Participant Variables
- Variables connected with the research participants
> eg. intelligence, age, gender and personality - Controlled through the experimental design eg. matched pairs
> Random allocation - control participant variables by reducing bias
