We studied Introspection method and Observation method used in psychology of learning. But these methods lack scientific objectivity and validity. Experimental method is the most scientific and objective method of studying behaviour. It is the method, which is responsible for assigning the status of Science to Psychology.
Let us learn more about this Experimental method.
In 1879, William Wundt established the first psychological laboratory at Leipzing in Germany. Since then, experimental method in psychology has become popular, Experimental method consists of actions performed under pre-arranged or rigidly controlled conditions.
Here the emphasis is on experimentation. Experimentation is where the investigator controls the educative factors to which a group of children are subjected during the period of inquiry and the investigation observes the resulting achievement.
J. W. Best describes, “Experimental research is the description and analysis of what will be, or what will occur under carefully controlled conditions.”
a. Experiments are always conducted in laboratory. Hence the laboratory is essential.
b. Psychological experiments performed in this method essentially require two people; the experimenter or group of experimenters who perform the experiments and the other is the subject or subjects on whom the experiment is performed.
c. The key factor in this method is the controlling of conditions or variables. The term ‘Variable‘ means that which can be varied or changed.
By controlling the variables we can eliminate the irrelevant conditions and isolate the relevant ones. We thus become able to observe the causal relationship between the phenomena keeping all other conditions almost constant. Let us understand this by an example. If we try to study the effect of intelligence on academic achievement by the experimental method, we will need to determine the causative relation between the two phenomena (variables)- i.e. intelligence and academic achievement. One of these variables, the effect of which we want to study will be called the independent variable and the other the dependent variable. Thus the independent variable stands for cause and the dependent variable is the effect of the cause. Other conditions like study-habits, sex, socio-economic conditions, parental education, home environment, health, past learning, memory etc. which exercise a good impact upon one‘s achievement, besides one‘s intelligence, are termed “interviewing variables”. In Experimentation, all such interviewing variables are to be controlled, i.e. they are to be made constant or equalized and the effect of only one independent variable e.g. intelligence (in the present case), on one or more dependent variable is studied. The interviewing variables made constant, are hence called as controlled variables.
Steps in the experimental method
1. Raising a problem:
In any experiment the first steps is to identify a problem. For example it has been observed that the students cheat in the examinations. To stop this, it many recommend strict supervision. But it has also been seen that even when there is strict supervision there is cheating, hence there crops up the problem of cheating under strict supervision or relaxed supervision. This problem may lead to experimentation.
2. Formulation of a hypothesis:
The next step in experimental method is the formulation of a hypothesis that “Strict supervision may lead to less copying in the examination as compared to the relaxed supervision. “This hypothesis is now to be tested by experiment.
3. Making a distinction between Independent and Dependent variables:
In the example given above, the cheating behaviour of the students will be dependent variable while the nature of supervision will be the independent variable. It is because by changing the supervision the cheating behaviour is expected change. In the present experiment we manipulate the conditions of supervision in order to discover the ways in which they determine the dependent variable that is the cheating behaviour. We may observe the effect of supervision in the experimental situation and also the effect of relaxed supervision under similar conditions and with the same group of students.
4. Controlling the situational variables:
The experiment will not give valid results unless the situational variables are controlled. If the experiment is conducted with different set of students who have been trained in a different manner of have a different value system then the results will be different in comparison to those who have been subjected to experiment earlier. Similarly the other conditions like the person who is supervising the place of supervision etc. have to be controlled. This means that all those conditions, which might affect the dependent variable, are to be controlled. Since, in any experiment there are numerous conditions which are needed to be controlled, it is many a time difficult to do so. Hence we take recourse to various types of experimental designs, which we have described earlier.
5. Analysis of the Results:
Once the experiment is concluded the results are analysed. In our example we may apply simple percentages to find out in which type of supervision a higher percentage of students have copied. Many a times we apply more sophisticated statistics to analyse the results.
6. Verification of Hypothesis:
The last step in the experimental method is the verification of the hypothesis, which we have earlier framed. The result of the experiment exhibits whether the hypothesis is accepted or refuted. We may find that strict supervision leads to less copying. In that case we may conclude that our hypothesis is accepted. If the results are otherwise then our conclusion will be that the hypothesis is refuted.
Experimental method is the most precise, planned, systematic and controlled method of studying behaviour. It uses a systematic procedure called as experimental design. The term experimental design has two different meanings-one is the experimental design which represents the six basic steps we have referred above which are followed in an experiment. The second meaning of experimental design is selecting an appropriate statistical procedure. Experimental design provides important guidelines to the researcher to carry out his research study. Experimental design ensures adequate controls by avoiding irrelevant causes of variability. The layout of a design depends on the type of the problem the investigator wants to investigate. No one design solves all the problems of a research study.
A variety of experimental designs have been developed by researchers in recent years. These designs differ as these are dependent upon:
a) The nature of problem
b) The situation
c) The subjects and their availability.
Merits of experimental method
Experimental method being most precise and scientific has following merits:
1. Experimental method is the most systematic method or getting reliable data.
2. Experimental method enables accurate observations due to controlled conditions.
3. It allows us to establish cause effect relationship between different phenomena.
4. The results obtained are valid and reliable.
5. The findings of the experimental method are verifiable by other experiments under identical conditions.
6. It helps to protect from the subjective opinions. Hence it provides objective information about the problem.
7. It provides adequate information about the problem.
8. In experimental method, experiments are conducted under vigorously controlled conditions. The experimenter can control the application and withdrawal of independent variables.
9. Experimental method increases ones knowledge or psychological facts in child psychology, social and abnormal psychology.
It is rightly said the experimental method has made psychology a science.
Demerits of the method
Experimental method suffers from various following demerits:
1. Experimental method is a costly and time consuming method as it requires a laboratory and apparatus to conduct it properly.
2. Experiments are conducted in artificially determined pattern of behaviour. In real life situation it is quite different.
3. It needs specialized knowledge and therefore every teacher cannot be expected to conduct the experiment.
4. The scope is limited. All problems of psychology cannot be studied by this method as we cannot perform experiments for all the problems that may come up in the diverse subject matter of psychology.
5. Accurate measurements, in case of human beings, are never possible.
6. It is difficult to always control the independent variable. Therefore it is not possible to create desired conditions in laboratory.
7. It is not possible to reach certainty in matters of social science s including educational psychology.