Types of Experiment
Laboratory Experiments
These are conducted in highly controlled environments. It does not always have to be a lab, it could
for example, be a classroom where conditions are well controlled.
Strengths
Have high control over extraneous variables. This is to ensure that the manipulation of the IV
is causing an effect on the DV only-we can be surer about cause and effect. (high internal
validity)
Replication is more possible because of high levels of control. This is to ensure that new
extraneous variables are not produced when repeating an experiment- checks that findings
are valid and not just a one-off.
Limitations
Lack generalizability- the lab experiment may be artificial and not like everyday life.
It has low external validity as in an unfamiliar context, participants may behave in an unusual
way so their behaviour cannot be generalized beyond the research setting.
May lead to demand characteristics.
Low mundane realism- the tasks often do not represent real-life experience.
Field Experiments
In field experiments, the IV is manipulated in a natural, more everyday setting.
Strengths
Have higher mundane realism because the environment is more natural in comparison to lab
experiments- may produce behaviour which is more valid and authentic.
High external validity- participants may be unaware they are being studied.
Limitations
Loss of control of extraneous variables.
Precise replication is often not possible.
Important ethical issues- participants cannot consent being studied and this is an invasion of
privacy.
The cause and effect between the IV and DV in field studies may be much more difficult to
establish.
Natural Experiments
Natural experiments are when the researcher takes advantage of a pre-existing independent
variable. This kind of experiment is called natural because the variable would have changed even
experimenter was not interested. It is to be noted that it is the IV that is natural, not necessarily the
setting, participants may be tested in a lab.
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Laboratory Experiments
These are conducted in highly controlled environments. It does not always have to be a lab, it could
for example, be a classroom where conditions are well controlled.
Strengths
Have high control over extraneous variables. This is to ensure that the manipulation of the IV
is causing an effect on the DV only-we can be surer about cause and effect. (high internal
validity)
Replication is more possible because of high levels of control. This is to ensure that new
extraneous variables are not produced when repeating an experiment- checks that findings
are valid and not just a one-off.
Limitations
Lack generalizability- the lab experiment may be artificial and not like everyday life.
It has low external validity as in an unfamiliar context, participants may behave in an unusual
way so their behaviour cannot be generalized beyond the research setting.
May lead to demand characteristics.
Low mundane realism- the tasks often do not represent real-life experience.
Field Experiments
In field experiments, the IV is manipulated in a natural, more everyday setting.
Strengths
Have higher mundane realism because the environment is more natural in comparison to lab
experiments- may produce behaviour which is more valid and authentic.
High external validity- participants may be unaware they are being studied.
Limitations
Loss of control of extraneous variables.
Precise replication is often not possible.
Important ethical issues- participants cannot consent being studied and this is an invasion of
privacy.
The cause and effect between the IV and DV in field studies may be much more difficult to
establish.
Natural Experiments
Natural experiments are when the researcher takes advantage of a pre-existing independent
variable. This kind of experiment is called natural because the variable would have changed even
experimenter was not interested. It is to be noted that it is the IV that is natural, not necessarily the
setting, participants may be tested in a lab.
1
