Überprüfung von Steuerungssystemen zur Strophenanwahl der Amsel durch digitale Simulierung

Abstract

Output analysis and input-output experiments had given evidence for five sequential effects occuring independently of each other in the singing behavior of blackbirds (Fig.1). Recently these investigations resulted in a model which summarized the interaction of five functional components evaluated from the found effects; thereby the model explained the data processing controlling the sequential patterning of the behavior (Fig. 2) — During the investigations reported here, this model and alternative models were tested by means of computer programs. Main question: Would the models generate sequences of patterns equivalent to the sequence of vocal patterns produced by a blackbrid? Results:

• 1) Only the original one of the tested models generated sequences of patterns showing the specific regularities and their characteristic variations corresponding to natural blackbird songs. This brought evidence for a multiplicative mode of interaction between the “component of throttling-back” (Drosselungskomponente) and the other four components; furthermore for a terminal functioning of the “extreme-value-passage” (Extremwertdurchlaß) (Figs, 2–4 and 10).

• 2) Concerning the “component of periodicity” (Periodikkomponente) the mechanism of a “reset of periods” was falsified while the mechanism of a “continued periodicity” could be made evident. This implied: The periodicity of the single pattern (phrase) runs over the course of the whole song: the proceeding of the oscillation takes place with each output realisation (Fig. 5).

• 3) Variations of values of the particular parameters given to the different components during the testing programs showed that a) extreme values resulted in “unnatural” sequences of patterns; b) only values lying within distinct intervals generated sequences containing the whole set of the postulated effects; c) exactly with those parameter values, with which one of the effects could get produced in a natural form, also the other effects were generated correspondingly optimal (Figs. 6–8).

• 4) The differential variation of the values of the particular parameters given to the components (during the testing programs) allowed a lot of predictions concerning the consequences of increasings or decreasings in the strength of the different components. These predictions have to be tested by experiments with natural systems (blackbirds) (Fig. 9; Tables 1–3).