The processes which occur in the brain that determine consciousness, whatever their location, are not well understood. Clearly, as discussed earlier, combinatorics show that individual cells are not each responsible for one object. It still remains likely that, however, that sets of cells respond specifically to ecologically and evolutionarily significant objects. For example, people easily recognize objects which resemble faces, and small moving objects are often assumed to be mice or snakes.

What, then, occurs in the brain to determine awareness? Regardless of the location of the consciousness neurons, other neurons are responsible for determining the characteristics of objects, such as color, shape, and location. Since multiple neurons must cooperate to respond to an object, each object has a set of neurons attached to it. How, though, do these neurons know with which other cells to cooperate to identify an object?

Evidently, certain neurons "bind" together while working on the same object. There are three main types of this binding. The first and second are "hardwired" into the brain, serving to recognize commonly encountered objects, while the third is nearly entirely transitory, recognizing things which have never before been seen.

The first type of binding is predetermined genetically. This type includes the recognition of faces and snakes seen above. At some point in history, evolution favored those individuals who were born able to recognize these objects. Such recognition occurs not only in humans, but also in lower organisms, such as flies. The evolutionary advantage given by these adaptations is fairly clear.

The second type of binding arises from frequently being exposed to (overlearning) a particular situation. For example, this type of binding occurs while learning an alphabet. Together with the first type of binding, overlearning is the result of strengthened connections between neurons.

These two types of binding cannot, however, cover every possible object which could be encountered. Thus, the brain must be able to form new connections rapidly in response to new stimuli. Repeated circumstances of this third type of binding lead eventually to the second type described above.

Having thus classified binding, we still do not know exactly what binding is. Several theories exist, however, as to how the brain is able to achieve this binding, and hence distinguish between different objects.