In neurobiological terms, a memory is a stored pattern of links between nerve cells in the brain. It is created when synapses in a network of neurons are activated for a short time. The more often the memory is recalled afterwards, the more likely it is that permanent links develop between the nerve cells -- and the pattern will be stored as a long-term memory. In theory there are so many possible links that an almost unlimited number of memories can be permanently stored.
So why don't all people have the same powers of recollection as Jill Price? "If we could remember everything equally well, the brain would be hopelessly overburdened and would operate more slowly," says McGaugh. He says forgetting is a necessary condition of having a viable memory -- except in the case of Price and the other three memory superstars.
For McGaugh, there is another reason why people with such phenomenal memory are so puzzling. They challenge a theory on which his research has been based for the last half a century. This theory, based on clinical observation, says memories are stored in greater detail and with more staying power when they are tied to emotion.
