4.1. CONCEPT MANIPULATION. Humans have the biological capability for developing abstractions and concepts. They can mentally manipulate these concepts to a certain extent, and "think" about situations in the abstract. Their mental capabilities allow them to develop general concepts from specific instances, predict specific instances from general concepts, associate concepts, remember them, etc. We speak here of concepts in their raw, unverbalized form. For example, a person letting a door swing shut behind him suddenly visualizes a person behind him carrying a cup of hot coffee and some sticky pastries. Of all the aspects of the impending event, the spilling of the coffee and the squashing of the pastry somehow are abstracted immediately and associated with a concept of personal responsibility combined with a fear of the consequences. But a solution comes to mind immediately as an image of a quick stop and an arm extended back toward the door, with motion and timing that could prevent the collision, and the solution is accepted and enacted. With only nonverbal concept manipulation, we could probably build primitive shelter, evolve strategies of war, hunt, play games, and make practical jokes. But further powers of intellectual effectiveness are implicit in this stage of biological evolution (the same stage we are in today).