SHIELDING MODELS: Any model has the tendency to become stable. There are some models which cannot become stable. Such models can destabilize the whole structure of models due to some infinite loops performed in order to gain stability (the model with problems will activate some other models, including the PSM, in a continuous way). A shielding model is created by the main ZM. It intercepts some truths which can activate some other models (incuding the PSM) and transmits to the model with problems some information which stabilizes it. The reality generated by a shielding model is called "illusion". The best known shielding-model is religion. This shielding model stabilizes any model which predicts the death of the person so it blocks the activation of the PSM. STORY-TYPE MODELS: Faced with a new external reality, the normal tendency of the brain is to make a normal model, or to activate a suitable model from its collection of models. But, when the external reality is changing very fast, this procedure cannot be followed. In this case, the brain records the information based on short-range models. These short-range models are connected between them based on the order of occurence. Such a model (string- type) is called "story-type model". Story-type models are used later ("off line") to make or improve the normal models. PROTECTION AND SURVIVAL MODEL (PSM) This is the fundamental image model of any brain. When a new being is born, the brain contains only the PSM. The PSM contains a collection of basic short range models (e.g. reflex actions) and long-range models (e.g. the instincts) for a minimal protection of that being and to ensure the unconditional survival of that being, forever (these are the basic design features). The PSM contains also a model of the external body (bones, muscles, and so on) and also some basic models of interaction with the external reality (e.g. the model to follow with the eyes the movement of an entity from external reality, or the model to touch an entity from external reality, which is in the range of the hand). There are also some models to ensure the equilibrium of the physical body. Faced with a new external reality, the PSM is activated and it tries to solve the problem, based on its short-range models (e.g. reflex actions), but it will also create a new element, which is associated to the new external reality. Once the new element is created by PSM, this element is self- developing as a model, in order to understand the new external reality. When such an external reality occurs again, the specialized model created during the first occurence of the new external reality will be activated instead of the PSM. Such models are normal models (they do not belong to PSM). Thus, as a new born being gains experience, the PSM will not be activated, but the models previously created in the interaction of that being with the external reality.