Figure 1

The Funnel-Model of the sequential organization of the male rat behavior. The model is based on a transition analysis of the behavioral elements of the male rat occurring during a series of experiments, which included feeding behavior, sexual behavior and territorial aggression, combined with the effects of electrical stimulation of the ventromedial hypothalamic nucleus (VMH). Explanation: see text. We have coined this model the ‘Funnel-Model’, because it illustrates clearly that in phase 1 of the behavioral sequence the animal is relatively free to make choices leading to any possible ‘consummatory act’, or in a wider view, to any behavioral state. Phase 1 can be characterized as a transitional situation, from where any behavioral sequence leading to a specific consummatory act can be performed or from where any possible behavioral state can be reached. At the end of phase 2 the situation is completely different: the male is ‘bound to’ perform the consummatory act, (mostly consisting of a series of physiological reflexes) and the opportunity to select other behavioral transitions is temporarily blocked. Only after completing the consummatory behavior, the ‘freedom’ of phase 1 is available again. The ‘Funnel-model’ illustrates on the one hand that physiological and brain mechanisms are working to support behavioral perseverance and to keep behavior directed to a specific goal, while on the other hand, especially in phase 1, the opportunity is raised to choose another strategy, or to pursue another goal or to reach another state.