RT Journal
T1 THe influence of caffein on mental and motor efficiency and on the circulation
JF JAMA
JO JAMA
YR 2012
FD March 21
VO 307
IS 11
SP 1118
OP 1118
DO 10.1001/jama.2012.167
UL http://dx.doi.org/10.1001/jama.2012.167
AB 
H. L. Hollingworth,1 professor of psychology at Columbia University, gives a summary of an extended investigation soon to be published in psychologic journals, on the influence of caffein on menial and motor efficiency. The experiments were carried on in a specially equipped laboratory with the aid of six assistants and sixteen subjects, of both sexes, engaged for full-time service extending over a period of forty days. The most rigorous scientific method and precaution were employed throughout the investigation, the full details of which will appear in the complete report. Controls were employed among both the subjects and the assistants. These controls received capsules containing sugar of milk instead of caffein, and no subject knew whether or when he received caffein. The tests performed included motor efficiency measured by steadiness, coordinated movements, typewriting, etc., and mental efficiency measured by speed and accuracy of calculations, discriminations, and other mental processes. The same program of tests was performed for an hour five times each day. A condensed statement of the author's conclusions from 76,000 measurements and 800 efficiency curves with and without caffein follows: