Validity Flashcards
What are the three types of validity?
- Ecological Validity
- Population Validity
- Construct Validity
What is the definition of validity?
How accurate a piece of research or test is at measuring what it aims to measure (is the study measuring what it is supposed to measure?)
What is the background to validity?
- What we want to measure is the dependent variable (DV)
- If we are measuring anything apart from the DV by mistake, then the study is not valid
Why could Milgram not tell his participants that the study was about obedience in the first place?
- If participants realised the study was about obedience, they might not act naturally
- They could either act more obedient (because they think the experimenter wants that and they want to please him)
- Or they might be less obedient because they want to ‘beat’ the experimenter
- Either way, we are not measuring their obedience anymore and therefore the study is not valid
Independent variable (IV) meaning
An aspect of the experiment that is manipulated to see its effect on a particular behaviour - the behaviour that is tested
Dependent variable (DV) meaning
The measure of behaviour in an experiment. Assuming the experiment is properly controlled, it can be assumed to be affected by the IV
Extraneous variable (EV) meaning?
An undesirable variable that might affect the relationship between the IV and DV (EVs reduce validity)
Demand characteristics meaning
When the participants realise the true purpose of a study and act differently
What is the meaning of ecological validity?
Where research is true to life (does the study represent a real-life situation)
Why is ecological validity important?
We want to understand how people behave in their everyday lives. However, often psychological research takes place in lab-like settings which don’t resemble anything that would happen in “real life”
What is the meaning of population validity?
How accurately a sample represents its intended population (ability to generalise to other groups of people)
Why is population validity important?
Researchers want to understand how as many people as possible behave. However, research just uses samples of participants who may behave completely differently from other people not included in the research
What is the meaning of internal validity?
Where research does not have lots of extraneous variables and the effect of the IV on the DV is truly being measured
What is the meaning of external validity?
Where research can be generalised to other setting (e.g. population validity and ecological validity)
ECOLOGICAL VALDITY - MILGRAM
What could participants do in the study?
Administer electric shocks to another person every time they got an answer wrong on a memory test
ECOLOGICAL VALDITY - MILGRAM
Explain why the study may lack ecological validity (which parts of the research seem to be unrealistic and not true-to-life?)
Not something most people would experience everyday
ECOLOGICAL VALDITY - MILGRAM
Which elements of the study do seem true to life? What parts have high ecological validity?
People working in the Nazi death camps were also required by authority figures to inflict harm upon other people
ECOLOGICAL VALIDTY - PILIAVIN
What could participants do in the study?
Decide whether to help somebody involved in a staged/fake incident on a subway train, i.e ill victim or drunk - collapsing in front of them
ECOLOGICAL VALIDTY - PILIAVIN
Explain why the study may lack ecological validity (which parts of the research seem to be unrealistic and not true-to-life?)
The study took place during the daytime (weekdays 11am - 3pm), so participants may not expect to see people drunk on the train at that time
ECOLOGICAL VALIDTY - PILIAVIN
Which elements of the study do seem true to life? What parts have high ecological validity?
Being on a subway train is something they would normally do and they may see drunks on the train anytime of the day
ECOLOGICAL VALIDITY - BANDURA
What could participants do in the study?
Watch a role model attack a bobo-doll for 10 minutes and then be put into a room with lots of toys
ECOLOGICAL VALIDITY - BANDURA
Which elements of the study do seem true to life? What parts have high ecological validity?
Children may normally see adults being aggressive in other situations
ECOLOGICAL VALIDITY - BANDURA
Explain why the study may lack ecological validity (which parts of the research seem to be unrealistic and not true-to-life?)
Children would not normally see adults attacking toys
POPULATION VALIDITY - MILGRAM
What was the sample for the study?
40 males from the New Haven area. Ages 20 - 50
Wide range of occupations
POPULATION VALIDITY - MILGRAM
Why might the sample lack population validity? Why might it not be generalisable to others not in the research?
No females. Only collected from one area. Did not cover all occupations
POPULATION VALIDITY - PILIAVIN
What was the sample for the study?
4450 New York subway train passengers. 45% were black, 55% were white
POPULATION VALIDITY - MILGRAM
Why might the population validity to be considered high?
Was the same gender/age range of Nazi officers in second world war.
Study variations all over world
POPULATION VALIDITY - PILIAVIN
Why might the sample lack population validity? Why might it not be generalisable to others not in the research?
Only from one city. May have had many locals people on train
POPULATION VALIDITY - PILIAVIN
Why might the population validity to be considered high?
The study was carried out in New York, which is a very diverse city. The sample included people from different ethnic backgrounds
POPULATION VALIDITY - BANDURA
What was the sample for the study?
72 Children from Stanford Nursery School. Aged 3-5yrs.
36 boys, 36 girls
POPULATION VALIDITY - BANDURA
Why might the sample lack population validity? Why might it not be generalisable to others not in the research?
Only from one city. May have had many locals people on train
POPULATION VALIDITY - BANDURA
Why might the population validity to be considered high?
The study was carried out in New York, which is a very diverse city. The sample included people from different ethnic backgrounds
CONSTRUCT VALIDITY - MILGRAM
What was the study trying to measure?
How obedient participants are
CONSTRUCT VALIDITY - MILGRAM
Are there any factors (unrelated to the aim of the study - extraneous variables) that could have influenced participants’ behaviour?
Milgram didn’t do much to ensure participants were all psychologically healthy. Milgram would not have been testing obedience if a person enjoyed hurting people and shocked the learner for pleasure
CONSTRUCT VALIDITY - MILGRAM
What did the researcher do to try and ensure that they were measuring what they wanted to? (e.g. How were extraneous variables controlled for? Did participants know the aim of the study?)
The setting of Yale University and the use of trial shocks made it seem real. Participants stressful reactions suggested they thought it was real. Wide range of occupations controlled for possible individual differences in personality
CONSTRUCT VALIDITY - PILIAVIN
What was the study trying to measure?
How helpful participants are
CONSTRUCT VALIDITY - PILIAVIN
Are there any factors (unrelated to the aim of the study - extraneous variables) that could have influenced participants’ behaviour?
As the same train line/times were used it is possible some passengers on the trains saw the incidents more than once.
Cultural stereotypes or gender influences for helping behaviour were not assessed before the study (“its for men to help”)
CONSTRUCT VALIDITY - PILIAVIN
What did the researcher do to try and ensure that they were measuring what they wanted to? (e.g. How were extraneous variables controlled for? Did participants know the aim of the study?)
The victims always fell in the same place, so there is less chance of he environment changing the participants helping behaviour. Passengers didn’t know thy were taking part in a psychological experiment (and that the ‘victim’ wasn’t collapsing for real)
CONSTRUCT VALIDITY - BANDURA
What was the study trying to measure?
If participants imitate role models
CONSTRUCT VALIDITY - BANDURA
Are there any factors (unrelated to the aim of the study - extraneous variables) that could have influenced participants’ behaviour?
The bobo-doll was not real. Children may react differently to a toy compared to a real person
CONSTRUCT VALIDITY - BANDURA
What did the researcher do to try and ensure that they were measuring what they wanted to? (e.g. How were extraneous variables controlled for? Did participants know the aim of the study?)
Conditions were all controlled standardised - all children were given the same trials/conditions. Differences in aggressive behaviour showed these differences
EXAM STYLE QUESTION
Evaluate the validity of Milgram’s study of obedience (6 marks)
The study by Milgram can be seen to have construct validity as the aim of the study was hidden from participants. For example, the posters that were used to recruit participants stated that the study they were volunteering for was about “memory and learning”, not obedience (the real aim of the study). This is beneficial because participants would not have acted naturally had they known their obedience was being tested. As participants were not told the true aim, we can assume the participants responses accurately reflected their true levels of obedience.
The study by Milgram can be seen to lack population validity because.. the sample was only males. For example, there were only 40 20-50 yr old males used, no females or people over 50 or under 20. This is a problem because the ability to compare or generalise results to other groups of people is important in Psychology and in this case the ability to do so is extremely limited (i.e. low population validity).
