There are, however, various types of study which differ materially from each other according to the subject matter or to the type of response required. Some study involves comparatively little thinking. The directed activity must be present, but the choice, the judgment, may need to be exercised only in the beginning when methods of procedure need to be selected, and later on, perhaps, when successes or failures need to be noted and changes made in the methods accordingly. Another type of study needs continual thinking of the most active sort all the way through the period. Just the proportion of the various factors involved in thinking which is present at any given study period must be determined by the response. A type of study which would be completely satisfactory for one subject needing one response, would be entirely inadequate for another subject needing another response. To illustrate, in some cases the study must deal with habit formation. The need felt is to learn a mechanical response of a very definite nature to this situation; the problem is to get that response. The thinking would come in in deciding upon the method, in watching for successes, in criticizing progress, and in judging when the end was obtained. A large part of the time spent in study would, however, need to be spent in repetition, in drill. Of such character is study of spelling, of vocabularies, of dates; study in order to gain skill in adding, or speed in reading, or to improve in writing or sewing. Much of habit formation goes on without study--in fact, to some it may seem to be ludicrous to use the word "study" in connection with the formation of habits. It is just because the study elements in connection with responses of this type have been omitted that there has been such a tremendous waste of time in teaching children to form right habits. This omission also explains the poor results, for the process has been mechanical and blind on the part of the student. At the other extreme in types of study is that which can be used in science and mathematics, in geography and history, when the major part of the time is given to selecting and rejecting suggestions and seems required by the goal. In this type the habituation, the fixing of the material, comes largely as a by-product of the factors used in the thinking.