The requirement is to cross out a particular letter in a connected text.  Every one of the thirty women in the classroom received the same first page of a newspaper of that morning.  I emphasize that it was a new paper, as the newness of the content was to secure the desired distraction of the attention.  As soon as the signal was given, each one of the girls had to cross out with a pencil every “a” in the text for six minutes.  After a certain time, a bell signal was given and each then had to begin a new column.  In this way we could find out, first, how many letters were correctly crossed out in those six minutes, secondly, how many letters were overlooked, and, thirdly, how the recognition and the oversight were distributed in the various parts of the text.  In every one of these three directions strong individual differences were indeed noticeable.  Some persons crossed out many, but also overlooked many, others overlooked hardly any of the “a’s,” but proceeded very slowly so that the total number of the crossed-out letters was small.  Moreover, it was found that some at first do poor work, but soon reach a point at which their attention remains on a high level; others begin with a relatively high achievement, but after a short time their attention flags, and the number of crossed-out letters becomes smaller or the number of unnoticed, overlooked letters increases.  Fluctuations of attention, deficiencies, and strong points can be discovered in much detail.

The third test which was tried with the whole class referred to the intelligence of the individuals.  Discussion of the question how to test intelligence in general would quickly lead us into as yet unsettled controversies.  It is a chapter of the psychology of tests which, especially in the service of pedagogy but to a certain degree also in the service of medicine, has been more carefully elaborated than any other.  Often it has been contested whether we have any right to speak of one general central intelligence factor, and whether this apparently unified activity ought not to be resolved into a series of mere elementary processes.  The newer pedagogical investigations, however, speak in favor of the view that besides all special processes, or rather, above all of them, an ability must be recognized which cannot be divided any further, and by which the individual adjusts his knowledge, his experiences, and his dispositions to the changing purposes of life.  The grading of the pupils in a class usually expresses this differentiation of the intelligence; and while the differences of industry or of mere memory and similar secondary features may sometimes interfere, it remains after all not difficult for an observant teacher to grade the pupils of his class, whom he knows well, according to their general intelligence.  The psychological experiments carried on in the schoolroom have demonstrated that this ability can be tested by the measurement of some very simple mental activities.  The best method would be the