Modeling Hydra Behavior Using Methods Founded in Behavior-Based Robotics

7.2. Generation of behavioral organizer 417.2 Generation of behavioral organizerAs previously described, a priority-based interaction of the behaviors in Hydra is suggestedin the literature. Thus, behavioral organization using the CSA is straight-forward,and can be accomplished by organizing the behaviors in layers with respect to priorities,using switches of suppression type for the behavioral inter-connections. Fig. 7.10 showsthe resulting behavioral model.B4: FeedingB3: Response to light✓✏ ❄S✒✑MotivationalstateB2: Response to mechanical stimulus✓✏ ❄S✒✑HydraactionB1: Spontaneous actions✓✏ ❄S ✲✒✑Figure 7.10: Structure of colony-style behavioral organizer for the behaviors of Hydra. Here, Srepresents switches of suppression-type.In behavior selection situations, in biological organisms as well as in artificial systems, itis common that some trade-off is necessary [40]. Thus, it would be desirable to investigateto what extent the suggestion of priority-based behavior organization in Hydra holds.However, not enough results from experiments on the physical animal were found in theliterature to enable such an investigation at this point. In Chapter 8, recommendationsfor further experiments with respect to this are discussed. To validate the model in otheraspects, a set of simulation experiments were carried out, the results of which will nowbe described.7.2.1 Experiment A: Spontaneous locomotion patternsWagner recorded the position of Hydra, when the animal was left undisturbed for severaldays. His results suggest that the spontaneous locomotion behavior of Hydra is much like