Basic concepts essentials of experimental method a. Experiments are always conducted in laboratory. Hence the laboratory is essential. b. Psychological experiments performed in this method essentially require two people the experiment or group of experimenters who perform experiment 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 and example. If we try to study the effect of intelligence on academic 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-eco 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 present case, on one or more dependent variable is studied. The interviewing variables made constant, are hence called as controlled variables.