This is a presentation that I have created which goes through the different sections of AS Psychology Unit 1 research methodology.

1. Psychology – Unit 1
Research Methodology

2. Experimental
Design:

3. Independent Groups
This is where different participants are used in two separate conditions of the independent variable.
Evaluation
• Avoids order effects as participants are only used in one condition, if they were used in many they may become tired,
bored, etc.
• A higher amount of participants are needed. This may be expensive if a volunteer sample was used.
• Differences in participants may cause participant variables such as sex, gender, age to affect results.

4. Repeated Measures
The same participants are involved in each condition of the independent variable. Each condition of the experiment
uses the same group of participants.
Evaluation:
• Fewer participants are required therefore the process is made quicker and potentially cheaper if a volunteer
sample was used.
• They are convenient and more economical to carry out.
• There may be order effects as participants have encountered the first condition and know what to do in the second
one.
• May lack generalisability if a smaller and more restricted sample is used.

5. Matched Pairs
A pair of participants is used, one each in different condition. However they are matched on things such as age,
gender etc.
Evaluation:
• Reduces participant variables as the researcher has tried to create a group based on characteristics
• They avoid order effects as separate groups are used for separate conditions.
• It is very time consuming trying to find participants that have similar characteristics.
• Lacks ecological validity as it may not be normal for participants to be surrounded by people who are so similar to
them.

6. Sampling
Techniques

7. Random Sampling:
Random samples require a way of naming or numbering the target population and then using some type of raffle
method to choose those to make up the sample. Random samples are the best method of selecting your sample
from the population of interest.
The advantages are that your sample should represent the target population and eliminate sampling bias, but the
disadvantage is that it is very difficult to achieve (i.e. time, effort and money).
Stratified Sample:
Where the researcher identifies the different types of people that make up the target population and works out the
proportions needed for the sample to be representative.
Gathering such a sample would be extremely time consuming and difficult to do (disadvantage). This method is
rarely used in Psychology. However, the advantage is that the sample should be highly representative of the target
population and therefore we can generalize from the results obtained.
Opportunity Sample:
Uses people from target population available at the time and willing to take part. It is based on convenience.
An opportunity sample is obtained by asking members of the population of interest if they would take part in your
research. An example would be selecting a sample of students from those coming out of the library.
This is a quick way and easy of choosing participants (advantage), but may not provide a representative sample, and
could be biased (disadvantage).
Volunteer Sample:
Used to attract participants. Usually done through an advert e.g. Milgram’s study. An advantage is that participants
are debriefed and have given their consent before the test has even begun. A disadvantage is that it is time
consuming and potentially expensive.

8. Research Methods

9. Surveys
A survey is an umbrella term for surveys and questionnaires. It is an experimental gathers self-report data on people’s
feelings and attitudes.
Questionnaires:
These involve closed questions which gather quantitative data, as it keeps the answers to the questions as figures and
percentages.
Evaluation:
• The data is measurable and easy for the researcher to interpret as it is quantitative. This makes it easy for the
researchers to compare the data.
•The questions are standardised meaning it can be repeated.
•Closed questions can lack ecological validity as questions and answers may not provide an everyday representation of
the participant’s feelings and attitudes.
Interviews:
These are different to questionnaires, in that they tend to involve open questions which gather qualitative data. This gives
the researcher a more in-depth, detailed view of the participants feelings and attitudes.
Evaluation:
• They can provide a lot of detail as the data is qualitative and therefore participants can give detailed, in-depth answers.
• They use open questions which ultimately make the process of an interview a lot more time consuming.
• Quantitative data isn’t measurable therefore it is very hard for the researcher to compare the data.

10. Lab Experiments
This type of experiment is conducted in a well-controlled environment – not necessarily a laboratory – and therefore
accurate measurements are possible. The researcher decides where the experiment will take place, at what time,
with which participants, in what circumstances and using a standardised procedure. Participants are randomly
allocated to each independent variable group.
Evaluation:
• It is easy to repeat as a standardised procedure is used.
• The researcher has full control over extraneous variables.
• Lacks ecological validity as participants are in an artificial environment.
• May cause demand characteristics as participants are in an unusual environment.

11. Field Experiments
Field experiments are done in the everyday (i.e. real life) environment of the participants. The experimenter still
manipulates the independent variable, but in a real-life setting (so cannot really control extraneous variables).
Evaluation:
•Behaviour in a field experiment is more likely to reflect life real because of its natural setting, i.e. higher
ecological validity than a lab experiment.
•There is less likelihood of demand characteristics affecting the results, as participants may not know they are
being studied. This occurs when the study is covert.
•There is less control over extraneous variables that might bias the results. This makes it difficult for another
researcher to replicate the study in exactly the same way.

12. Natural Experiments:
Natural experiments are conducted in the everyday (i.e. real life) environment of the participants but here the
experimenter has no control over the IV as it occurs naturally in real life.
Evaluation:
• Behavior in a natural experiment is more likely to reflect life real because of it natural setting, i.e. very high ecological
validity.
• There is less likelihood of demand characteristics affecting the results, as participants may not know they are being
studied.
• Can be used in situations in which it would be ethically unacceptable to manipulate the independent variable, e.g.
researching stress.
• They may be more expensive and time consuming than lab experiments.
• There is no control over extraneous variables that might bias the results. This makes it difficult for another researcher to
replicate the study in exactly the same way.