Can we now formulate any general principle by which the later and more artificial interests connect themselves with these early ones that the child brings with him to the school?

Fortunately, we can:  there is a very simple law that relates the acquired and the native interests with each other.

Any object not interesting in itself may become interesting through becoming associated with an object in which an interest already exists.  The two associated objects grow, as it were, together:  the interesting portion sheds its quality over the whole; and thus things not interesting in their own right borrow an interest which becomes as real and as strong as that of any natively interesting thing. The odd circumstance is that the borrowing does not impoverish the source, the objects taken together being more interesting, perhaps, than the originally interesting portion was by itself.

This is one of the most striking proofs of the range of application of the principle of association of ideas in psychology.  An idea will infect another with its own emotional interest when they have become both associated together into any sort of a mental total.  As there is no limit to the various associations into which an interesting idea may enter, one sees in how many ways an interest may be derived.

You will understand this abstract statement easily if I take the most frequent of concrete examples,—­the interest which things borrow from their connection with our own personal welfare.  The most natively interesting object to a man is his own personal self and its fortunes.  We accordingly see that the moment a thing becomes connected with the fortunes of the self, it forthwith becomes an interesting thing.  Lend the child his books, pencils, and other apparatus:  then give them to him, make them his own, and notice the new light with which they instantly shine in his eyes.  He takes a new kind of care of them altogether.  In mature life, all the drudgery of a man’s business or profession, intolerable in itself, is shot through with engrossing significance because he knows it to be associated with his personal fortunes.  What more deadly uninteresting object can there be than a railroad time-table?  Yet where will you find a more interesting object if you are going on a journey, and by its means can find your train?  At such times the time-table will absorb a man’s entire attention, its interest being borrowed solely from its relation to his personal life. From all these facts there emerges a very simple abstract programme for the teacher to follow in keeping the attention of the child:  Begin with the line of his native interests, and offer him objects that have some immediate connection with these.  The kindergarten methods, the object-teaching routine, the blackboard and manual-training work,—­all recognize this feature.  Schools in which these methods preponderate are schools where discipline is easy, and where the voice of the master claiming order and attention in threatening tones need never be heard.