Experimental methods
Experimental methods offer one of the most common ways of collecting
evidence in psychology.
What is meant by the experimental method in psychology?
By using an experiment a researcher can intervene directly in the
situation, which is being investigated.
It has greater potential to seek and find the causes and effects than
other methods.
The experiment is the most powerful of the research methods.
Types of experimental methods
Many regarded the experiment as the preferred method of scientific
enquiry
There are four main types of experiment
1) Laboratory experiment
2) Field experiment
3) Natural experiment
4) Quasi experiment
How are they all similar?
As they are all experiments, they all involve the use of an independent
variable and a dependent variable.
How do they differ?
They differ in the level of control they have over variables.
, The laboratory experiment
The laboratory experiment has been a leading method used in
psychology.
What is a laboratory experiment?
A laboratory experiment is an experiment conducted in a special
environment where variables can be carefully controlled the
research manipulates the independent variable and records the
effect on the dependent variable.
Why are the variables carefully controlled?
Using the same environment for every participant means the external
factors such as noise levels and lighting are highly controlled so that they
are the same for all participants in the study.
Examples?
a) Many memory experiments are carried out under controlled
conditions because psychologists are keen to control situational
variables which may affect attention such as noise and heat.
These factors are kept constant under laboratory conditions.
b) Behaviourists also favour laboratory experiments.
Controlled conditions allow behaviourists to manipulate one stimulus
to elicit a response while keeping all other stimuli the same (for
example, the number of people in the environment.)
A laboratory experiment also allows random allocation of
participants to conditions where appropriate.
This makes it a true experiment as the psychologist cannot
influence who participates in which condition.
Why is it important to allow for this?
In this sense, findings cannot be accused of bias.
, Strengths of the laboratory experiment
1. Control over variables
High levels of precision can be achieved.
Laboratory experiments offer a high control over extraneous
variables than in other settings or with other research methods as the
environment is also controlled.
Why is this a strength?
Control over variables makes it easier to reliably establish cause and
effect between the independent variable and the dependent
variable.
Why?
In other words, if an experimenter observes a change in the
dependent variable, it is highly likely to be due to the independent
variable- high internal validity.
Experimental methods offer one of the most common ways of collecting
evidence in psychology.
What is meant by the experimental method in psychology?
By using an experiment a researcher can intervene directly in the
situation, which is being investigated.
It has greater potential to seek and find the causes and effects than
other methods.
The experiment is the most powerful of the research methods.
Types of experimental methods
Many regarded the experiment as the preferred method of scientific
enquiry
There are four main types of experiment
1) Laboratory experiment
2) Field experiment
3) Natural experiment
4) Quasi experiment
How are they all similar?
As they are all experiments, they all involve the use of an independent
variable and a dependent variable.
How do they differ?
They differ in the level of control they have over variables.
, The laboratory experiment
The laboratory experiment has been a leading method used in
psychology.
What is a laboratory experiment?
A laboratory experiment is an experiment conducted in a special
environment where variables can be carefully controlled the
research manipulates the independent variable and records the
effect on the dependent variable.
Why are the variables carefully controlled?
Using the same environment for every participant means the external
factors such as noise levels and lighting are highly controlled so that they
are the same for all participants in the study.
Examples?
a) Many memory experiments are carried out under controlled
conditions because psychologists are keen to control situational
variables which may affect attention such as noise and heat.
These factors are kept constant under laboratory conditions.
b) Behaviourists also favour laboratory experiments.
Controlled conditions allow behaviourists to manipulate one stimulus
to elicit a response while keeping all other stimuli the same (for
example, the number of people in the environment.)
A laboratory experiment also allows random allocation of
participants to conditions where appropriate.
This makes it a true experiment as the psychologist cannot
influence who participates in which condition.
Why is it important to allow for this?
In this sense, findings cannot be accused of bias.
, Strengths of the laboratory experiment
1. Control over variables
High levels of precision can be achieved.
Laboratory experiments offer a high control over extraneous
variables than in other settings or with other research methods as the
environment is also controlled.
Why is this a strength?
Control over variables makes it easier to reliably establish cause and
effect between the independent variable and the dependent
variable.
Why?
In other words, if an experimenter observes a change in the
dependent variable, it is highly likely to be due to the independent
variable- high internal validity.
