82 PSYCHOLOGY AND PREACHING
consciousness and therefore to call forth less and less feel ing; and after a while its cessation will call forth an un pleasant feeling-tone. In this way an acquired taste is formed and a craving for a certain kind of stimulus. One s daily life affords so many confirmations of the statement that it needs no demonstration.
But daily experience also presents certain facts which do not seem to conform to this law, and which require explana tion. On examination they appear to be only apparent exceptions. For instance, one may be so situated that he hears a noise repeated at intervals. At first it may excite very little feeling at all ; but its repetition attracts attention, and, as the attention is directed towards it, becomes increas ingly pleasant or unpleasant, as the case may be. By reason of the direction of the attention to it the sensibility of the organism to that particular sound is heightened for a time and the pleasure or displeasure which it causes grows greater with repetition during that time. In this way a morbid state of extreme sensibility may be induced, and a noise (or any other stimulus) which at first was practically indifferent may come to excite a high degree of feeling. It constitutes, however, only an apparent exception to the law of adaptation stated above. The repetition produces more intense feeling for a time only because on account of the special conditions the normal sensibility of the organism to that stimulus is temporarily increased ; and all the while the law of adaptation has been operating, and when the special causes which produced the abnormal sensibility have ceased to operate, it will be found that the feeling response to that experience will be less in proportion to the number of times it has been repeated. Habit has supervened, and in order to secure a feeling response equal to the first one it is neces sary to increase the strength of the stimulus about in propor tion to the number of repetitions. Exactly what the ratio is experimental Psychology has not been able to state with precision. It seems that the strength of the stimulus must be increased in something like geometrical ratio. This is
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