Experimental Methods Flashcards
Outline and Evaluate Laboratory, Field, Natural, and Quasi experiments
Name the 4 types of experimental methods
- Laboratory
- Field
- Natural
- Quasi
What do all experimental methods have in common ?
All attempting to find a cause-and-effect relationship
Summary of Experimental Methods (Actions the researcher takes for the Setting, IV, DV)
Laboratory Experiment -
- setting: controlled conditions
- IV: manipulates the IV
- DV: measures the DV
Field Experiment -
- settings: natural conditions
- IV: manipulates the IV
- DV: measures the DV
Natural Experiment -
- settings: natural conditions
- IV: IV is naturally occurring
- DV: measures the DV
Quasi Experiment -
- settings: natural conditions/controlled conditions
- IV: IV is a difference between people
- DV: measures the DV
Outline a Laboratory Experiment
Experiments conducted under specified controlled conditions in which the researcher manipulates the independent variable (IV) to measure its effect on the dependent variable (DV).
The conditions are heavily controlled in order to minimise the effect of any extraneous variable, to prevent them from becoming confounding variables which might adversely affect the DV.
Participants will be aware that they are taking part in an investigation due to the contrived nature of the situation which may feel unlike real-life.
Evaluation of Laboratory Experiments
Strength - high degree of control over extraneous variables –> high internal validity –> as allows cause-and-effect to be established
Limitation - lacks external validity –> artificial nature of environment means lack of ecological validity –> study cannot be generalised beyond the lab as tasks often lack mundane realism
demand characteristics may occur –> as ppts know they’re being investigated —> behaviour can change in unnatural manner
Outline a Field Experiment
An experiment carried out in natural conditions, in which the researcher manipulates the independent variable (IV) to measure the effect on the dependent variable (DV).
The ‘field’ is considered any location which is not a lab.
Participants in a field experiment typically are unaware that they are taking part in an investigation with a view to observing more natural behaviour
Evaluation of a Field Experiment
Strength - high ecological validity –> results more likely to be representative of behaviour witnessed in everyday life
Limitations - natural conditions means less control over extraneous variables –> can become confounding variables which negatively impact DV –> distort findings, firm cause-and-effect relationship cannot be drawn due to other factors
ethical issues - ppts unaware –> cannot give informed consent –> as such research may involve breach of privacy rights and cost-benefit analysis will need to be conducted before proceeding with any study to ensure the perceived outcomes from the research will outweigh any personal costs to those involved
Outline a natural experiment
An experiment whereby the researcher does not manipulate the independent variable and instead examines the effect of an existing IV (e.g. earthquake or flood) on the DV.
The behaviour of the people affected is either compared to their behaviour beforehand, or with a control group who have not encountered the IV.
The IV itself is natural, not necessarily the context in which the investigation takes place as it could take place in a lab
Evaluation of a Natural Experiment
Strength - high external validity –> high ecological validity as real life issues are being studied rather than IV being manipulated artificially
unique insights into real-life situations from using this methodology –> allows for research to be conducted into areas of psychology that could not be generated for ethical reasons or because of logistical and practical constraints
Limitations - No control over environment and subsequent extraneous variables –> hard to establish cause-and-effect
naturally occurring event may be rare which limits opportunity to generalise results to other events
Outline and quasi experiment
An experiment that contains a naturally occurring IV, but one which already exists, ppts cannot be randomly allocated
The IV is the difference between people such as age, gender, personality trait
The researcher measures the effect of this IV on the DV.
The experiments do not have to be conducted under natural settings, although they often are, they can be conducted in controlled conditions (lab)
Evaluation of a Quasi Experiment
Strength - allow researchers to compare different types of people easily to provide insights into similarities and differences between these groups which could not be ethically generated otherwise
Limitations - not free from bias –> ppts cannot be randomly allocated –> the level of IV to which they belong is predecided–> cannot be certain on whether other dispositional or environmental factors played a role in the outcome
