Take part in a natural environment
- Greater ecological validity since the IV is naturally occurring.
- Increased validity of findings due to lack of experimenter manipulation.
Impossible to replicate exactly. Unreliable.
- Difficult to infer cause and effect due to lack of control over extraneous variables and no manipulation of IV.
Take place in artificial controlled environment
- Manipulation of Independent variables can indicate cause and effect relationships
- Standardised procedures mean that replication is possible.
- Artificial conditions may produce unnatural behaviour, which means that the research lacks ecological validity.
- Results may be biased by sampling, demand characteristics and/or experimenter effects.
Take place in a natural environment but IV is still controlled
- Greater ecological validity since the surroundings are natural.
- Less likelihood of demand characteristics (if participants unaware they are being studied)
- Difficulties in controlling the situation and therefore more possibility of bias from extraneous variables.
- Difficult to replicate exactly.
Independent Measures Design
An independent measures design is one that uses two or more conditions, with different participants in each condition.
- Participants only have to do the task once, so they are less likely to get bored or to work out what it is that is being tested (which may effect how they behave).
- As there are different participants in each group, there may be differences between them , which means that it is possible that the difference between them is what produced the difference in results.
Repeated Measures Design?
A repeated measures design is one that uses the same participants in each condition.
- The participants are in the same group, so it is easier to compare their performance in each condition.
- You need fewer participants as they will take part in each condition.
- The participants will do the same task twice, which may lead to boredom or improvement and may help them work out what is being tested
Matched Pairs Design
A matched pairs design is one where different participants are used in each condition but the researcher attempts to make the two groups of participants as similar as possible.
- Participants only have to be tested once. No order effects.
- Differences between groups have been reduced.
- A lengthy and time-consuming process that can be quite ‘wasteful’ of participants as a large number of people would need to be tested to find appropriate pairs.
A sample that has been selected in a way that means everyone has an equal opportunity of being chosen.
- Everyone in the target population has an equal chance of being selected.
- Sample is (or should be) representative of the target population.
- More complex and time consuming than other methods.
- Can be difficult (or even impossible) if the target population is large and the researcher does not that names etc.
An opportunity sample is one that is selected by ‘opportunity’, the researcher simply uses the people that are present at the time that he or she is conducting the research
- Quick and easy to select the sample as you simply take advantage of the people that are around you when you conduct your research.
- No need to select people because of predetermined categories or characteristics.
- May be biased as unlikely to be representative of a target population.
Self Selected Sampling?
A self selected sample is one where people volunteer to take part in a research project.
- May be a relatively easy way of achieving a sample.
- Can target/ request participants who may possess the features needed for the investigation.
- May be biased as likely to have volunteers with similar characteristics e. g helpfulness.
- Unlikely to be representative of a larger population.
Single blind design?
A single blind design is one where the participants are unaware of the aims of the research
- May reduce bias or demand characteristics.
- Causes ethical problems of deception
Double blind design?
A double blind design is one where a second experimenter is used to gather the data – one who has no knowledge of the aims of the research.
- This reduces the possibility of the experimenter being able to bias the research
Describing a procedure for an experiment
- Type of experiment: Lab/Field/Quasi
- Sample: Type (oppotunity/random/self selected), where, when, who?
- Experimental Design : Independent/Repeated/Matched pairs
- IV, DV, Procedure
- Description of materials eg. word list
- Conditions: Where and how?
- Recipe: Ethics and controls!!
- Scoring: Quantitative/Qualitative (nominal, ordinal, interval)
MY **** AND DELIGHTFUL EX CRUSH REMAINS SINGLE