AS RM Flashcards
What is an Independent Variable (IV)?
- Variable that the researcher manipulates in order to determine its effect on the DV
- To provide a standard against which experimental conditions can be compared there may be a control condition where the IV is not manipulated at all
What is a Dependent Variable (DV)?
Variable that is being measured
What is Operationalisation?
Is defining the variables in such a way to make them measurable
What are Extraneous Variables (EV)?
Variables (other than the IV) that COULD affect the DV
What are Confounding Variables (CV)?
Variables (other than the IV) that HAVE affected the DV
What are the 4 types of experimental methods?
- Laboratory
- Field
- Natural
- Quasi
- Laboratory Experiments
Carried out in a controlled environment allowing researcher to exert high level of control over IV + eliminate any EV
What does it mean to be randomly allocated to a condition?
- Means neither the experimenter nor the participant decides which condition the participant is placed in
- An unpredictable method is used to decide: flipping a coin or drawing names out of a hat
Advantages of Lab Experiments
- High level of control —> easy to control for any EV + prevent them from becoming CV
- As researcher can manipulate the IV —> can establish a cause and effect relationship between IV and DV
- Well controlled lab experiment can be easily replicated (easily conducted) by others + if findings are similar to the original study then the results are reliable
What does it mean that results are reliable?
The study can be conducted repeatedly with the same results being found each time which means the results are not due to chance or confounding variables
Disadvantages of Lab Experiments
- Strong chance of demand characteristics (type of EV where participants guess what the experiment is about + alter their behaviour)
- High level of control means it lacks mundane realism + doesn’t have ecological validity
What is mundane realism?
The extent to which an experiment reflects real life
What is ecological validity?
The ability to generalise the findings of research to the real world
What is a field experiment?
- Carried out in the real world
- IV is manipulated by the researcher to see the effect on the DV
Advantages of field experiment
- More mundane realism + ecological validity than lab
- As researcher can manipulate the IV —> cause and effect relationship between IV and DV can be established
- Less chance of demand characteristics as participants may not even be aware they are taking part in research
Disadvantages of field experiments:
- Less control over EV so the effect on the DV may not be caused by the IV but by these EV —> means research is not valid (not measuring what it intends to)
- Less control over sample
- Difficult to replicate
What are natural experiments?
The researcher takes advantage of a naturally occurring IV to see its effect on the DV
Advantages of natural experiments:
- High level of mundane realism + ecological validity
- Very useful when it is impossible or unethical to manipulate the IV/sample in a lab or field experiment
Disadvantages of natural experiments:
- Less control over EV
- Difficult to replicate
- Difficult to determine cause and effect
What are Quasi Experiments?
Contain a naturally occurring IV
However in a quasi the naturally occurring IV is a difference between people that already exists (e.g. gender or age)
The researcher examines the effect of this variable on the DV
Advantages of quasi experiments:
- Controlled conditions - hence replicable + likely to have high internal validity
Disadvantages of quasi experiments
- Cannot randomly allocate participants to conditions so there may confounding variables presented + makes it harder to conclude that the IV caused the DV
What is an observation?
When a researcher watches or listens to participants engaging in the behaviour that is being studied
What is a correlation?
- A correlation is a technique for analysing the strength and direction of the relationship between two variables known as co-variables
- The strength of the variable is known as the correlation coefficient