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Society of Mind

11.7 predestined learning

It would be wonderful if we could classify all behavior into two types: built-in and learned. But there simply is no clear-cut boundary between heredity and environment. Later, I'll describe an agency that is sure to learn one particular thing: to recognize human beings. But if such an agency is destined to end up with a certain particular behavior, is it reasonable to say that it learns? Since this type of activity appears to have no common name, we'll call it predestined learning.

Every child eventually learns to reach for food. To be sure, each different child lives through a different history of reaching-act experiences. Nevertheless, according to our theory of nearness models of space, all those children will end up with generally similar results because that outcome is constrained by the nearness relations of real-world space. Why make the brain use a tedious learning process when the final outcome seems so clear? Why not build in the answer genetically? One reason could be that learning is more economical. It would require an enormous store of genetic information to force each separate nerve cell to make precisely the right connections, whereas it would require much less information to specify the construction of a learning machine designed to unscramble whatever irregularities result from a less constrained design.

This is why it isn't sensible to ask, Is the child's conception of space acquired or inherited? We acquire our conceptions of space by using agencies that learn in accord with processes determined by inheritance. These agencies proceed to learn from experience — but the outcomes of their learning processes are virtually predestined by the spatial geometry of our body parts. This kind of mixture of adaptation and predestination is quite common in biology, not only in the brain's development but in that of the rest of the body as well. How, for example, do our genes control the shapes and sizes of our bones? They may begin with some relatively precise specification of the types and location of certain early cells. But that alone would not be adequate for animals that themselves have to adapt to different conditions; therefore those early cells must themselves be programmed to adapt to the various chemical and mechanical influences that may later be imposed on them. Such systems are essential for our development, since our organs must become able to perform various tightly constrained activities, yet also be able to adapt to changing circumstances.

Perhaps the growth of the Society-of-More is another instance of predestined learning, for it seems to develop in every normal child without much outside help. It seems clear that this complex agency is not built directly by inborn genes; instead, we each discover our own ways to represent comparisons — yet we all arrive at much the same final outcome. Presumably, genetic hints must help with this by supplying new layers of agents at roughly the right times and places.