Variation is one of the most obvious characteristics of human behavior. An individual’s every day life is marked by an expansive fluctuation in almost every aspect of behavior such as the intelligence he exudes, the speed with which he moves, his expression of emotions, goals he pursues, humor, energy, anxiety, shyness, among others. Even the most intelligent of human individuals have ordinary thoughts most of the time as they too are confronted with the normal activities like choosing the right mode of dressing, brushing in the morning and carrying out normal transactions. There is sufficient evidence towards the fact that one of the most striking features of a child’s behavior is its dynamic aspect of the stream of behavior recorded continuously (Barker, 1968). Any individual with no knowledge of psychology comprehend this dimension of human variation from their observation and experience. However, this is not prominent in scientific psychology.
The concern of scientific psychology is another dimension of behavior variability with emphasis on individual differences. This is a major step in psychology that despite the variations that occur within every individual’s behavior, the methods for measuring and identifying individual behavior constants have been devised. Scientific psychology’s concern is with the varied number of constants measured and how they relate with each other. There is however a difficulty in achieving a stable behavior measurement. For the stability of behavior measurement to be