discussion of original tendencies and inheritance from near ancestry, i.e., that the physical correlate of all types of mental activity is a definite forming of connections between particular bonds-these connections, of course, according to the laws of readiness exercise, and effect, would be determined by the situation acting as a stimulus and would, therefore, vary as the total situation varied.  They believe in a highly specialized human brain, which reacts in small groups of nerve tracts—­not in gross wholes.  They would express each of the “elemental” powers in the plural and not in the singular.

The basis of this change of view within the last fifteen or twenty years is to be found in experimental work.  The question has definitely been put to the test as to how far training in one line did influence others.  For a full description of the various types of experiments performed the reader is referred to Thorndike’s “Psychology of Learning,” Chapter 12.  Only an indication of the type of work done and the general character of the results can be given here.  Experiments in the effect of cross education, in memorizing, in observing and judging sensory and perceptual data, and in forming sensori-motor association habits have been conducted in considerable numbers.  A few experiments in special school functions have also been carried out.  Investigations in the correlation between various parts of the same subject and between different subjects supposed to be closely allied also throw light upon this subject.  The results from these different lines of experiment, although confusing and sometimes contradictory, seem to warrant the belief stated above.  They have made it very clear that the question of transfer is not a simple one, but, on the contrary, that it is extremely complex.  They make plain that in some cases where large transfer was confidently expected, that little resulted, while, on the other hand, in some cases when little was expected, much more occurred.  It is evident that the old idea of a large transfer in some subtle and unexplained way of special improvements to a general faculty is false.  But, on the other hand, it would be equally false to say that no transfer occurred.  The general principle seems to be that transfer occurs when the same bonds are used in the second situation to the extent that the alteration in these particular connections affects the second response.  Both the knowledge of what bonds are used in various responses and to what extent alteration in them will affect different total responses is lacking.  Therefore, all that is at present possible is a statement of conditions under which transfer is probable.