The Monotony-Threshold in Singing Birds

Abstract

WHAT stimulates animal organisms is change; what deadens response is sameness, or persistent repetition.This is true especially of repetition at brief intervals; for with long intervals, the "attention span" is exceeded, there is fading of "memory" in the immediate or active sense.(Latent memory, conditioning with associative recall, is another matter; even in a bird it may span long periods; but we are speaking of what needs no recall, since it has yet to be forgotten.)With long intervals, brain cells perhaps revert approximately to their previous state, other activities intervene, and thus the tenth or hundredth occurrence of the repetitive factor is experienced in its contrast with these intervening events, or with a certain "freshness," and not as monotonously repetitive.If then there could be "intolerable monotony" for an animal, it would be produced by many repetitions unrelieved by substantial pauses.Applying this to bird song, we deduce that a bird which sings the same song over and over will probably have marked pauses between reiterations