Research Methods

Experimental Methods

Different types of experiment

  • Lab




  • Field




  • Natural/Quasi




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Laboratory Experiment

  • Laboratory Experiment: An experiment that is carried out in a special, tightly controlled environment is classed as laboratory.

Advantages: Cause and effect: We can usually see that the IV has caused the alteration in the DV. Provided we have controlled our experiment we should be able to show that it was the coffee that was responsible for the faster reaction times.

Replication: Provided care has been taken in conducting and reporting the procedure another person should be able to repeat your procedure to see if they get the same results.

Disadvantages: Lacks ecological validity: As we’ve seen so many times (e.g. in memory and in Milgram), experiments, especially those in laboratories are very artificial. Can they really tell us how people will behave in real life situations?

Demand characteristics: New one for you; this refers to participants behaving differently because they know they’re being watched. We saw this in Milgram. It could be that they guess what you want and try to please the experimenter, e.g. by obeying!

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Field Experiment

Field Experiment: These are experimental investigations carried out in the natural environment of those being studied. E.g in homes or schools or on the street.

Advantages: Improved ecological validity - by carrying out an experiment in its natural settings, this means that It has real life application.

Demand Characteristics: Participants are less likely to be conscious that they are taking part in a study or experiment and therefore the influence of demand characteristics is more likely to be reduced.

Disadvantages: Ethics - If patients are unaware of the study how can the consent to take part or withdraw from the experiment?

Control: The experimenter has less control over the environment so more variables may affect the outcome.

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Natural Experiment

Natural Experiment: Natural experiments take advantage of a naturally occurring event. The researcher makes use of the naturally occurring differences in the independent variable.

Advantages: Research opportunities - it is possible to research events that it would be unethical to study any other way or that may be impossible to set up.

Demand Characteristics: Participants would be less conscious that they are taking part in an experiment therefore reducing demand characteristics.

Disadvantages: Loss of control - The investigator does not directly have control to the IV tour cannot assign participants to experimental conditions. Therefore it is difficult to establish a cause-and-effect relationship.

Replication: In some cases clearly impossible, in others very difficult. As a result it may be impossible to check the validity of research.

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Observation Techniques

In observation research, behaviour is observed and records and there is usually no deliberate manipulation of variables. This research can differ in several important ways, depending on:

The study setting: Naturalistic vs Controlled

Advantages of naturalistic: High in ecological validity since it has not been tainted by observer intervention with the observed not usually knowing that their behaviour is being watched.

  • There are no demand characteristics as it is a natural environment as if they are not aware they are being watched they cannot alter their behaviour.

Disads: Observation could be research bias, the observers interpretation could be different from another's observers interpretation.

  • Not knowing you’re being watched creates issues with privacy and participants not consenting to take part.
  • You cannot be certain what factors are creating the behaviour being observed.
  • Also hard to replicate therefore it lacks the reliability factor.

Controlled observation: These allow for greater control of confounding variables meaning it is easier to establish cause and effect relationships. However, they are lower in ecological validity since the trigger for the behaviour is usually not a natural event.

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Observation Tech. 2

The role of the Researcher

Disclosed vs Undisclosed
Dis: Participants know they are being observed. This reduces ethical issues of consent and privacy but reduces validity due to increased demand characteristics.

UnDis: Participants are unaware of the observation. This raises ethical issues (privacy and consent) but increases validity by reducing demand characteristics.

Patricians vs non-participants
Here the researchers get involved with the group of participants they are observing. This can be seen as unethical as is is deceiving the participants, however if there is no deception, the researcher may not get the results they need because of demand characteristics.

The more likely scenario in which participants are observed from a distance rather than the researchers infiltrating the group. This allows the researcher to observe without interfering.

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Observation Tech. 3

The structure of the observation

The observer may use a coding system in order to count the number of times specific behaviours occur. Categories are needed so that the observer can count the number of times each behavioural category occurs during a given period of time. This kind of approach produces quantitative data that can be analysed statistically.

The observer will obtains information through detailed verbal descriptions of the behaviour which they observe.

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Correlational analysis

Correlations do not have an IV and DV and nothing is manipulated as with an experiment. A correlational analysis involves the comparison of two co-variables. This is used to see the association nope the relationship between to variables and if there even is any.

Types of Correlation:

Positive - as one variable increases so does the other

Negative - as one variable in crease ps the other decreases

No Correlation - there is no relationship between the two variables.

Ads: Correlations allow us to study links between variables that could not be studied in any other way. We can use a correlational analysis to show a possible link between the two occurring naturally.

Disads: Just because there is a relationship between the two variables does not mean that one cause the other, therefore there is still the problem of cause-and-effect.

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Self-Report Techniques - Interviews.

Structured: These usually aim to produces quantitative data and include questions that are decided in advance in order to structure and categorise the interviewee's response.

Semi-structured: This is usually the most successful as there are some prepared questions by the interviewer but there are also some additional questions that provide opportunities for the interviewee to expand on their answer.

Unstructured: these are usually more difficult to analyse as there is more freedom for the interviewee to say what they like as the questions are more broader due to no structure.

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Self-Report Tech. 2 - Questionnaires

This is a list of written questions that is able to gather lots of relevant information relatively quickly and cheaply.

Closed: These are when the researcher determines the range of possible answers. E.g How old are you - 13 14 15?

Open: These are when the researcher does not limit the possibilities of answers. E.g What did you do for your birthday?

Leading: These are when the questions are written in such a way that causes the respondent to reply in a certain way. E.g You do like psychology don't you?


  • The Researcher cannot influence results
  • Simplicity
  • If the wording of the questions is ambiguous different respondents may interpret the questions differently and their answers may reflect this, therefore meaningful analysis of the respondent would be difficult to obtain.
  • Leading question may influence responses given.
  • Social desirability.
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Case Studies

This involves the in-depth study over time of a 'case', which is usually focuses on an individual or small group. These are longitudinal.


  • They give rich, in-depth data and detailed information


  • They are generalisable to everyone as the data only applies to one person or that small group.
  • Objectivity by the researchers can be difficult, with psychologists getting too close to patients.
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  • Ads: 
  • S - less likely for deviation, easier generalisability and simpler data analysis.
  • SS - allows for follow questions therefore there is more description and makes the interviewee feel more relaxed.
  • US - these have greater validity, as the interviewee will be more likely to say whatever they wish to express and the interviewer can be flexible in the approach they use
  • Disads:
  • S - There can be no follow up questions and it encourage brief less detailed answers.
  • SS - if the interviewer does not ask the right follow up question could cause problems. (Skills)
  • US - difficult to analyse and the interviewee may go off topic.
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