Validity : control of variables

Question 1

Confounding variables

Answer 1

• any variable which varies systematically with the independent variable - not manipulated by researcher
• can affect SOME participants behaviour not all
  e.g the idea that another factor can affect the dependent variable
  time of day - people tend to be more alert during the day and doing a test at this time could affect the results gained
  - experimenter should do tests at the same time of the day

Question 2

Extraneous variables

Answer 2

• variables do not vary systematically with the independent variable - not measured or manipulated by researcher
• affects ALL participants behaviour and can still have an effect on the dependent variable
• make it more difficult to determine a significant effect
  e.g placing people who have a better memory into a group where the the tv is on - does not show true effects as they already have decent memory

Question 3

mundane realism

Answer 3

• how an experiment mirrors the real world
  ‘mundane’ means of the world
• lack of mundane realism means something is not like everyday experience

Question 4

What does validity mean?

Answer 4

• how true or legitimate something is as an explanation to behaviour
• involves the issues of control, realism and generalisability
• can be split into internal and external validity

Question 5

Internal validity

Answer 5

• the degree to which an observed effect was due to the experimental manipulation rather than other factors such as confounding /extraneous variables
• concerns what goes on inside the study
  e.g whether the IV produced the change in the DV, whether the researcher tested what they wanted to test, whether the study lacked mundane realism

Question 6

How do you gain high internal validity?

Answer 6

• researcher must design the research carefully
• control confounding and extraneous variables
• ensure the researcher is testing what they want to test

Question 7

External validity

Answer 7

The degree to which a research finding can be generalised to other settings (ecological validity) , to other people (population validity) , over time (historical validity)
e.g the place where research was conducted, the people who are studied, the historical periodn
- affected by internal validity, cannot generalise the results of a study that was low in internal validity because the results have no real meaning for the behaviour in question