A test of muscular speed
Whether the result in such a performance as this varies from day to day, and is accidental, or whether it is constant and fundamental, can be determined by repeating the experiment from day to day. This repetition will also show whether improvement comes from practice.
If it is decided to repeat the experiment in order to study these factors, constancy and the effects of practice, some method of studying and interpreting the results must be found. Elaborate methods of doing this are known to psychologists, but the beginner must use a simpler method. When the experiment is performed for the first time, the students can be ranked with reference to their abilities, the fastest one being called “first,” the second highest, “second,” and so on down to the slowest performer. Then after the experiment has been performed the second time, the students can be again ranked.
A rough comparison can then be made as follows: Determine how many who were in the best half in the first experiment are among the best half in the second experiment. If most who were among the best half the first time are among the best half in the second experiment, constancy in this performance is indicated. Or we might determine how many change their ranks and how much they change. Suppose there are thirty in the class and only four improve their ranks and these to the extent of only two places each. This would indicate a high degree of constancy. Two different performances can be compared as above described. The abilities on successive days can be determined by taking the average rank of the first day and comparing it with the average rank of the second day.
If the effects of practice are to be studied, the experiments must be kept up for many days, and each student’s work on the first day compared with his work on succeeding days. Then a graph can be plotted to show the improvement from day to day. The average daily speed of the class can be taken and a graph made to show the improvement of the class as a whole. This might be plotted in black ink, then each individual student could put on his improvement in red ink, for comparison. A group of thirty may be considered as furnishing a fair average or norm in this kind of performance.
In connection with this simple performance, making marks as fast as possible, it is evident that many problems arise. It would take several months to solve anything like all of them. It might be interesting, for example, to determine whether one’s speed in writing is related to this simple speed in marking. Each member of the class might submit a plan for making such a study.
The foregoing simple study illustrates the procedure of psychology in all experimentation. A psychological experiment is an attempt to find out the truth in regard to some aspect of human nature. In finding out this truth, we must throw about the experiment all possible safeguards. Every source of error must be discovered and eliminated. In the above experiment, for example, the work must be done at the same time of day, or else we must prove that doing it at different times of day makes no difference. Nothing must be taken for granted, and nothing must be assumed. Psychology, then, is like all the other sciences, in that its method of getting its facts is by observation and experiment.
Summary. Science is systematic, related knowledge. Each science has a particular field which it attempts to explore and describe. The field of psychology is the study of sensitivity, action, and consciousness, or briefly, human behavior. Its main problems are development, heredity, instincts, habits, sensation, memory, thinking, and individual differences. Its method is observation and experiment, the same as in all other sciences.