The effect of stimulations, external or internal, is to 
     break up the unison of action of some part or the whole 
     of the brain. A speculative suggestion is that the 
     disturbance in some way breaks the unity of the actual 
     pattern that has been previously built up in the brain. The 
     brain then selects those features from the input that 
     tend to repair the model and to return the cells to their 
     regular synchronous beating. I cannot pretend to be able 
     to develop this idea of models in our brain in detail, but it 
     has great possibilities in showing how we tend to fit 
     ourselves to the world and the world to ourselves. In some 
     way the brain initiates sequences of actions that tend to 
     return it to its rhythmic pattern, this return being the act 
     of consummation, or completion. If the first action 
     performed fails to do this, fails that is to stop the original 
     disturbance, then other sequences may be tried. The