Measurement in Psychology

Abstract

IN the opening paragraph of “Psychology Down the Ages”, Prof. C. Spearman concludes a list of difficulties facing any who seek to define psychology, with the questions: “Do the data at its disposal include what can properly be called ‘measurements’? Is it, or can it ever hope to be, or should it as much as try to be, a systematic science at all?” Dr. William Brown, in the realm of medical psychology, answers the first question in the negative. Forced into metaphysics, he writes: “Determinism, although a postulate for psychology, cannot be accepted as anything proved. In physical science there is empirical proof of it to a certain extent through measurement. By measurement we can prove to a certain extent, within certain limits of error, the conservation of mass, the conservation of energy… But there is no measurement of that sort possible in psychology… The observations of psych-ology are primarily qualitative, not quantitative.” But the writer of “Essentials of Mental Measurement” could not leave it there. He added a footnote: “But mental measurement, in a derived form, is possible in the domain of mental tests and of the psycho-physical methods.”