brain associates, and meanings are associated.= We have already said something of the psychology of meaning (pp. 26 ff., 117 ff.); what can we now say of the associative functions of the brain? § 32. =Associative Tendencies: Material of Study.=—We want to find out how those processes in the brain which are the correlates of our ideas go together, get connected or associated. The brain is a machine; and it is not only complicated, but it is also plastic, that is, it is subject to change and modification. The _complexity_ of the machine makes it necessary for us to work with simple stimuli and by strict methods; only if we work with simple stimuli shall we get to the bare essentials of the associative functions; and only if we work by strict methods shall we obtain results which other investigators can repeat and verify. Even so, the _plasticity_ of the machine makes it impossible for us to lay down hard and fast laws of connection; we can speak only of connective tendencies or of =associative tendencies=; what actually happens, in any particular case, is likely to be the joint result of many tendencies, weak and strong, conflicting and concurring. The task before us is, therefore, not easy; but it is straightforward; and that is the next best thing. We want to find out how associative tendencies in the brain are set up; and to do this we must, evidently, find some way of _creating_ a bond between one nervous process and another; we must devise experiments in which we _make_ or _construct_ brain-connections. We need not look far afield; for we make such connections whenever we =learn= anything new; so that we have only to learn under experimental conditions, and the task is accomplished. But what shall we learn? what stimuli shall we employ in the experiments? ‘Words,’ you will say; and words have many advantages for learning; but they have, in this case, the supreme disadvantage that they are ingrained meanings. Words therefore will not do; but something very like them will. The question of the stimuli to be employed was, in fact, answered for us, thirty years ago, by the German psychologist Hermann Ebbinghaus, who—by one of those happy thoughts that come after long and intensive occupation with a subject—hit upon the notion of the =meaningless syllable=. Ebbinghaus made up over 2000 meaningless ‘words,’ all consisting of a vowel or diphthong between two consonants; syllables standing in the same relation to his own language that leb, rit, mon, yup, kig, wes, der, zam, for instance, bear to English. See the advantage of this kind of material for the work we have in view! The syllables are just like words, in that they may be seen, heard, or felt in the throat; they are unlike words, and vastly superior to them, in that they have no habitual associates; they lack context and meaning; every syllable in a series may be considered to have the same chances of making connections as every other. The material is so rich