(2 of 2)
The data from school records presents a much more definite and verifiable conclusion, viz., that the use of tobacco has distinctly harmful effects on the work of immature boys in grammar and high school, and to a lesser extent in college. Whether the effect is physiological or the product of other factors, such as idleness, social distraction, etc., is impossible to determine, but the accumulation of academic records from numerous sources leaves no doubt of the fact.
The core of the book, however, is the scientific study made in the psychological laboratory of the Uni-versity of Wisconsin. Most such investigations are vitiated by faulty methods or factors of interest, suggestion, deprivation, prejudices, etc. Dr. O'Shea and, his colleague, Dr. Clark L. Hull, determined to eliminate these subjective elements, and devised a "control" pipe, containing an electric heating coil. The subjects were given this while blindfolded and were surprised to learn later that they had not been smoking tobacco, but merely drawing in heated air. Seven non-smokers and nine smokers (university students) were tested for three hours on 18 consecutive days, on some of which they smoked actual tobacco before the tests, and on others only the "control." The tests included pulse beat, motor control (absence of tremors), tapping of a telegraph key, muscular fatigue, cancellation of letters for alertness and accuracy, memory span for digits, speed and accuracy in performing addition, reaction time to short, familiar words displayed, and facility in learning to associate symbols and nonsense syllables. To summarize the results, the tobacco smoking tended "to retard and to disturb intellectual processes, but not in a marked degree." There was great variability between persons and from day to day. In a few of the tests (e. g., speed in addition), tobacco increased the average efficiency of the group. In most of them, it decreased the average efficiency slightly, but in no case over 7%, except in muscular control. For all tests, the net average decrease was 5.13%, and more than half of this loss was from two extreme cases of nonsmokers, the non-smokers showing on the whole greater losses than the smokers, which may easily be accounted for by their lack of habituation to the drug.
From the laboratory data, the author concludes that it is impossible to say that tobacco smoking will retard the intellectual processes of any one person, but in a large group it may be predicted that the majority will be slightly retarded. Dr. O'Shea takes pains to point out that the study was limited to minor intellectual processes and gives no answer regarding creative ability, judgment or general physical vitality. Conclusive tests on these matters are still to be devised.
*Tobacco and Mental Efficiency—M. V. O'Shea—Macmillan. ($2.50).