Experimental Method

Experimental Method of Research

Before we get into the experimental method in psychology research, let's take a quick look at what are the basic components that make up scientific research.

Hypotheses and variables

The hypothesis is an important component of research. The hypothesis is formed at the start of an experiment with the purpose of stating what the researcher expects to find in their study. The hypothesis is important because it is used to identify if the results support or negate psychological theories.

The hypothesis needs to state the variables being investigated in the research.

There are other types of variables, such as extraneous variables, participant variables and situational variables. These are variables that may cause changes in the DV. Ideally, psychology research that follows the scientific method should not have these types of variables. However, it is next to impossible to control for every potential variable that should not affect the DV.

Stages of the experimental method in psychology research

The experimental method has a standardised procedure and has several fixed steps to it that are usually carried out in a lab setting.

1. Identify the topic of interest/research and form a hypothesis.
2. Identify the IV(s) and DV(s), determine the design and type of experiment, and determine how to measure the IV and DV, e.g. self-report measure, observations, etc.
3. Prepare the materials needed in the study and recruit participants through an appropriate sampling method.
4. Conduct the experiment in a carefully planned scientific manner, collect the data and statistically analyse the results.
5. Write up the lab report, evaluate the study and give suggestions for further research.

Experimental Method Example

A hypothetical study has been described below to show how the experimental method is used in psychology research.

There are several stages and requirements of research that follow the experimental method in psychology, freepik.com/pch.vector

The Features of the Experimental Method

There are three essential requirements of research that follows the experimental method.

1. Empirical
2. Reliable
3. Valid

We will now discuss each of these and identify how researchers can try and make sure that their research meets these requirements.

Research needs to be considered empirical. Empirical research means that the findings should be reflective of objective facts that the researcher has observed rather than their subjective opinion.

The next requirement, reliability, is important as it makes sure that research findings are consistent across time, in different situations, settings and when applied to other people. When research is found to be reliable, then it is thought that the research findings are representative of the population and can be applied to real-life settings.

The third requirement of research that follows the experimental method is validity.

Validity is important because if the researcher is not in fact measuring what they claim they are measuring, then the results are not accurate and cannot be accurately interpreted or applied. For example, if a test claims it measures personality type but instead measures emotion level, it cannot be a valid test.

The researcher should ensure that their subjective opinion does not influence the research methodology and analysis to ensure research is valid. Researchers can try and combat this through:

• Random allocation: Participants are randomly assigned to the experimental or control group; this is used to ensure that individual differences do not cause the results.

• Single/Double-blind technique: The researcher is unaware of which experimental condition the participants are in. This prevents the researcher from giving subconscious hints that may influence the participants' behaviour.

For research to be established as valid, the study's methodology and analysis should not be influenced by the researcher's subjective opinion, freepik.com/rawpixel.com

Types of Experimental Method in Psychology: Experimental Designs

The allocation of participants in experimental/ control conditions is important to ensure that a study is valid. The experimental design is the different ways the participants are split into different conditions/groups of the IV. There are different types of experimental designs.

The independent group's design (IGD)

The IGD is when different participants are assigned to each condition.

The advantages of this design are that it is less time-consuming than the alternative methods. As different participants are used for each condition there is less chance of participants guessing the hypothesis and altering their behaviour and order effects is not an issue.

However, the disadvantages of this design are that the researcher needs to recruit more participants compared to the other designs. Moreover, there is an increased chance of individual differences influencing the results.

The repeated measures design (RMD)

The RMD is when the same participants are used in all of the conditions.

The advantages of this design are that individual differences will not influence the results of the study as each participant is tested in both conditions and fewer participants may be required to be recruited in comparison to IGD.

In contrast, a disadvantage of this design is that there is a higher risk of order effects influencing the results. This is the idea that the order of conditions tested may influence the study's results.

The matched pairs design (MPD)

The MPD is when participants in each condition are matched on specific variables relevant to the study, e.g. gender, age, IQ, etc.

The advantages of the MPD are that there is no chance of order effects since each condition has a different set of participants and there is less risk of individual differences affecting the results since participants have been matched on such variables.

The disadvantages of this design are that matching participants may be a difficult, costly and time-consuming process.

Advantages and Disadvantages of the Experimental Method in Psychology

Let's move on to discuss the advantages and disadvantages of the experimental method as a whole.

Advantages of the experimental method

• The experimental method gives researchers a high level of control since they choose the IVs and DVs, how to measure them, and the procedure of the study. This means the studies are likely to be high in validity.
• Because of the standardised procedures, experiments can be replicated and their reliability can be tested.
• The experimental method allows cause and effect relationships to be determined, which is the goal of psychological research.
• The conclusions of these experiments allow useful applications to the real world.

Disadvantages of the experimental method

• Results are subject to human error and subjectivity, e.g. researcher bias, social desirability bias, order effects, etc and so it can be difficult to strictly adhere to the experimental method.
• The procedure of the experimental method can be time-consuming and costly.
• Can include practical problems, e.g. some variables may be hard to manipulate or measure.
• Extraneous variables sometimes can't be controlled, which can lower the validity of a study and its results.
• Participants' behaviour can be influenced by the researcher or the conditions of the experiment.