The Influence of Distraction upon Mental Test Performance 1The writers are grateful to Dr. Chester W. Darrow for his suggestions in this study, and also to Miss Eleanor Garm for her assistance in the statistical calculations.

The experiment to be reported here was carried out in connection with the examinations given in the process of selecting men for guides and policemen at the Century of Progress Exposition. While a number of tests were given and a great deal of data collected, this investigation is concerned only with the two tests of general intelligence which were used. It was assumed that many of the men selected as guides would, at times, be required to carry on their duties under distracting circumstances. It was further assumed that the men who would be least distracted from their tasks by disturbing influences would, other things being equal, make the better guides. We were therefore asked by those in charge of selecting the men to examine them for any differences which might be revealed in working under distracting or annoying conditions. Of course it was impossible to duplicate in the examining room either the actual work the guides would be required to do or the type of distracting circumstances under which they would be expected to work. It was taken for granted, however, that a measure of the influence of distractions