Types of Experiments in Psychology
This page provides an overview of four different types of experiments used in psychological research: laboratory experiments, field experiments, natural experiments, and quasi-experiments. Each type is described with its key characteristics, advantages, and disadvantages.
Laboratory Experiments
Laboratory experiments are conducted under controlled conditions where the researcher manipulates the independent variable (IV) to measure its effect on the dependent variable (DV). Participants are brought to the researcher's controlled environment.
Highlight: Laboratory experiments offer a high degree of control over extraneous variables, allowing for strong conclusions about cause and effect.
Advantages:
- High control over extraneous variables
- Strong internal validity
- Easy replication
Disadvantages:
- Lack of external and ecological validity
- Limited generalizability
- Presence of demand characteristics
Field Experiments
Field experiments take place in natural settings, where the researcher still manipulates the IV to measure its effect on the DV. Participants typically don't know they're part of a study.
Highlight: Field experiments provide greater ecological validity and external validity compared to laboratory experiments.
Advantages:
- Higher ecological validity
- Greater external validity
Disadvantages:
- Less control over extraneous variables
- Ethical concerns due to lack of informed consent
Natural Experiments
In natural experiments, researchers examine the effect of a naturally occurring IV on the DV without manipulation. These events could be natural disasters or other significant occurrences.
Definition: Natural experiments involve studying the effects of naturally occurring events on human behavior, comparing affected individuals to their pre-event behavior or to a control group.
Advantages:
- High external and ecological validity
- Unique insights into real-life situations
Disadvantages:
- Limited opportunities due to the rarity of natural events
- Reduced ability to generalize results
Quasi-Experiments
Quasi-experiments involve studying the effects of naturally occurring IVs that already exist, such as gender, age, or personality traits. These can be conducted in various settings.
Example: A researcher might study the effect of age (IV) on memory recall (DV) without manipulating the age variable.
Advantages:
- High control when conducted in laboratory settings
- Possibility of replication
Disadvantages:
- Lack of ecological validity in laboratory settings
- Limited generalizability
- Presence of participant variables due to non-random allocation
Vocabulary: Independent Variable (IV) - The factor manipulated or observed by the researcher. Dependent Variable (DV) - The outcome measured in response to changes in the IV.
This comprehensive overview of experimental types in psychology highlights the advantages and disadvantages of comparing laboratory and field experiments, emphasizes how natural experiments provide higher external validity and insights into real-life situations, and explains quasi-experiments with their naturally occurring independent variables.
