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Introduction
Page 1
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Experiment 1:
Intro/Method
Pages 2-3
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Experiment 1:
Results
Page 4
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Experiment 1:
Discussion
Page 5
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Experiment 2:
Intro/Method
Page 6
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Experiment 2:
Results
Page 7
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Experiment 2:
Discussion
Page 8
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Experiment 3:
Intro/Methods
Page 9
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Experiment 3:
Results
Page 10
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Experiment 3:
Discussion
Page 11
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General Discussion
Page 12
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Figures 1-2-3
Pages 13-14-15
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Tables 1-2-3
Pages 16-17-18
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The results of this study contradict the model of the offense motivational system as previously proposed (3). That model assumed that the effects of opponent sex and opponent familiarity were mediated by separate analyzers whose inputs converged in additive fashion on an offense motivational mechanism. It was further assumed that competitive fighting resulted from still another parallel input to the offense motivational mechanism. That model must be rejected. Another model is possible, however, which is consistent with the data obtained in this study.
One could assume that the motivating stimulus analyzers concerned with sex of the opponent do not have a direct effect on the offense motivational mechanism, but, instead, that they project to the motivating stimulus analyzer concerned with opponent familiarity. In other words, instead of converging in parallel and additive fashion on the offense motivational mechanism, the analyzers for opponent sex and opponent familiarity may be organized in a linear fashion, with the former projecting to the latter. If this were the case, one would only obtain effects of opponent's sex in offense against unfamiliar opponents, as in the case of territorial fighting but not in the case of competitive fighting.
The other differential effects obtained in the present study are all consistent with such a revised model. One may assume that gonadal hormones influence the offense system at two levels: the first is the set of analyzers of opponent sex; and the second is the synthesizer of competitive fighting.
Effects of gonadal hormones on analyzers of opponent sex have been proposed previously (3,5) and no modification is required by the present data. It is assumed that androgens activate two analyzers, one which is tuned to male opponent odors and which is facilitative, and a second which is tuned to female opponent odors and which is inhibitory .Further, it is assumed that estrogens activate a third analyzer that is tuned to male odors and which has an inhibitory effect on offense. According to the new model, these three analyzers would project to the analyzer of opponent familiarity.
Effects of gonadal hormones on competitive fighting have been clarified by the present experiment. It would appear that both androgens and estrogens facilitate the competitive fighting synthesizer, with the effect of the estrogens being stronger. Also, it would appear that the effect is both an organizing effect in perinatal development as well as an activating effect in adulthood, because some effect remains after gonadectomy.
The differential effects of food deprivation on territorial and competitive fighting are consistent with such a revised model. One may assume that the effects of food deprivation are not on the final common pathway of offense, the offense motivational mechanism, but rather on the analyzers and synthesizers which project to it. Hence, food deprivation enhances the activity of the competitive fighting synthesizer while it decreases the activity of the analyzers tuned to opponent sex and/or opponent familiarity.
Behavioral tests such as those described here can only establish hypotheses about the underlying structure of the offense system. We are presently engaged in brain research in search of data that would enable us to test these hypotheses and develop a definitive view of the way the brain makes the determination of when and how the animal should fighting.
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