made with the crossing-out of letters, we found that the smallest number of correctly marked letters was 107, the largest number in the six minutes, 272; the smallest number of overlooked letters was two, the largest 135; but this last case of abnormal carelessness stood quite isolated. On the whole, the number of overlooked letters fluctuated between five and sixty. If both results, those of the crossed-out and those of the overlooked letters, are brought into relations, we find that the best results were a case of 236 letters marked, with only two overlooked, and one of 257 marked, with four overlooked. The very interesting details as to the various types of attention which we see in the distribution of mistakes
over the six minutes were not taken into our final table. The word experiments by which we tested the intelligence showed that no one was able to reproduce more than twenty-two of the twenty-four words. The smallest number of words remembered was seven.
"The mistakes in the perception of distances fluctuated between one and fourteen millimeters; the time for the sorting of the forty-eight cards, between thirty-five and fifty-eight seconds; the association-time for the six associated words taken together was between nine and twenty-one seconds. The pointing experiments could not be made use of in this first series, as it was found that quite a number of participants
were unable to perform the act with the rapidity demanded.
"Several ways were open to make mathematical use of these results. I preferred the simplest way. I calculated the grade of the girls for each of these achievements. The same candidate who stood in the seventh place in the memory experiment was in the fifteenth place with reference to the number of letters marked, in the third place with reference to the letters overlooked, in the twenty-first place with reference to the number of word pairs which she had grasped, in the eleventh place with reference to the exactitude of space-perception, in the sixteenth place with reference to the association-time, and in the sixth place with reference
to the time of sorting. As soon as we had all these independent grades, we calculated the average and in this way ultimately gained a common order of grading. * * *
"With this average rank list, we compared the practical results of the telephone company after three months had passed. These three months had been sufficient to secure at least a certain discrimination between the best, the average, and the unfit. The result of this comparison was on the whole satisfactory. First, the skeptical telephone company had mixed with the class a number of women who had been in the service for a long while, and had even been selected as teachers in the telephone school. I did not know, in
figuring out the results, which of the participants in the experiments these particularly gifted outsiders were. If the psychological experiments had brought the result that these individuals who stood so high in the estimation of the telephone company ranked low in the laboratory experiment, it would have reflected strongly on the reliability of the laboratory method. The results showed, on the contrary, that these women who had proved most able in practical service stood at the top of our list. Correspondingly, those who stood the lowest in our psychological rank list had in the mean time been found unfit in practical service, and had either left the company of their own accord or else had been
eliminated. The agreement, to be sure, was not a perfect one. One of the list of women stood rather low in the psychological list, while the office reported that so far she had done fair work in the service, and two others, to whom the psychological laboratory gave a good testimonial were considered by the telephone office as only fair.
Theory and Practice