(a) data that is correct.
      (b) images that are an aid in acquiring new
          habits of forming efficient images.
      (c) standards of comparison, and constant demands
          for comparison.
      (d) such arrangement of elements that reasoning
          processes are stimulated.
      (e) conscious, efficient grouping.
      (f) logical association of ideas.

PROVISION FOR REPETITION OF IMPORTANT IDEAS.—­Professor Ebbinghaur says, “Associations that have equal reproductive power lapse the more slowly, the older they are, and the oftener they have been reviewed by renewed memorizing.”  Scientific Management provides for utilizing this law by teaching right motions first, and by so minutely dividing the elements of such motions that the smallest units discovered are found frequently, in similar and different operations.

BEST PERIODS FOR MEMORIZING UTILIZED.—­As for education of the memory, there is a wide difference of opinion among leading psychologists in regard to whether or not the memorizing faculty, as the whole, can be improved by training; but all agree that those things which are specially desired to be memorized can be learned more easily, and more quickly, under some conditions than under others: 

For example, there is a certain time of day, for each person, when the memory is more efficient than at other times.  This is usually in the morning, but is not always so.  The period when memorizing is easiest is taken advantage of, and, as far as possible, new methods and new instruction cards are passed out at that time when the worker is naturally best fitted to remember what is to be done.

INDIVIDUAL DIFFERENCES RESPECTED.—­It is a question that varies with different conditions, whether the several instruction cards beyond the one he is working on shall be given to the worker ahead of time, that he may use his own judgment as to when is the best time to learn, or whether he shall have but one at a time, and concentrate on that.  For certain dispositions, it is a great help to see a long line of work ahead.  They enjoy getting the work done, and feeling that they are more or less ahead of record.  Others become confused if they see too much ahead, and would rather attack but one problem at a time.  This fundamental difference in types of mind should be taken advantage of when laying out material to be memorized.

AID OF MNEMONIC SYMBOLS TO THE MEMORY.—­The mnemonic classifications furnish a place where the worker who remembers but little of a method or process can go, and recover the full knowledge of that which he has forgotten.  Better still, they furnish him the equivalent of memory of other experiences that he has never had, and that are in such form that he can connect this with his memory of his own personal experience.

The ease with which a learner or skilled mechanic can associate new, scientifically derived data with his memory, because of the classifications of Scientific Management, is a most important cause of workers being taught quicker, and being more intelligent, under Scientific Management, than under any other type of management.