A CRIMINAL HISTORY OF MANKIND

‘One afternoon I lay down in intellectual despair on a couch. Suddenly, out of an absolute quiet,
there came a firm, distinct loud voice from my upper right which said, “Include the knower in the
known!” It lugged me to my feet, exclaiming, “Hello?” looking for whoever was in the room. The
voice had an exact location. No one was there!’ It was an auditory hallucination, and the experience
led Jaynes to study the subject. He discovered that a surprisingly large number of ordinary people
have had auditory hallucinations. And in ancient texts - such as the Bible and the Iliad - Jaynes
found a total lack of evidence for any kind of introspection but an enormous amount for auditory
hallucinations - which were interpreted as the voice of God, or one of the gods.
In support of this part of his argument, Jaynes draws upon the relatively new discipline of splitbrain
research, based upon discoveries made by Roger Sperry in the 1950s (and for which he has
since received the Nobel Prize). The brain is divided into two halves, which appear to be mirrorimages
of each other. The specifically human part of the brain, as we saw in the last chapter, is the
part that presses against the top of the skull - the cerebrum. This looks rather like the two halves of
a walnut, joined in the middle by a thick bridge of nerves called the corpus callosum.
In the 1930s, it was discovered that attacks of epilepsy could be controlled by severing this bridge,
and so preventing the ‘electrical storm’ from spreading from one side to the other. And, oddly
enough, it seemed to make no difference whatever to the patient, who went about his business
exactly as before. It was Sperry who made the remarkable discovery that the split-brain patient
actually turns into two people; but they continue to work in such close cooperation that no one
notices. It is only when they are subjected to experiments that prevent them from co-operating that
the difference can be observed.
It has been known since the mid-nineteenth century that the left cerebral hemisphere controls our
powers of speech and reason, while the right seems to be concerned with intuition and with
recognising shapes and patterns. A patient whose left hemisphere has been damaged suffers from
impaired speech but can still appreciate art or enjoy music. A patient whose right hemisphere has
been damaged can speak perfectly clearly and logically, yet cannot draw the simplest pattern.
Oddly enough, the left side of the brain controls the right side of the body and vice versa. If
someone puts an object - say a key - into the left hand of a split-brain patient (without allowing him
to look at it), he knows perfectly well what it is, yet he cannot ‘put a name’ to it. If he is asked:
‘What are you holding in your left hand?’ he has no idea of the answer. For the person called ‘you’
seems to live in the left brain, and has no idea of what is concealed in his left hand.
With the eyes it is slightly more complicated, since half of each eye is connected to the left brain
and half to the right. But if the patient is asked to stare rigidly in one direction, an object can be
shown only to the left or right visual field. If a split-brain patient is shown an orange with the right
brain and an apple with the left, and is asked to write with the left hand what he has just seen, he
will write: ‘Orange’. If he is asked to state what he has just written, he will reply: ‘Apple’. When
one split-brain patient was shown an indecent drawing with the right half of the brain, she blushed;
asked why she was blushing, she replied: ‘I don’t know.’
There is therefore strong evidence that ‘you’ inhabit the left cerebral hemisphere, and that the
person in the right is a stranger. And although it could be argued that this does not apply to most of
us, since we are not split-brain patients, this inference would be incorrect. Otherwise, split-brain
patients would know that their corpus callosum had been severed - they would be aware that they
have been cut off from their ‘other half’. In fact, they notice no difference - which suggests that, for
practical purposes, they were already split-brain before the operation. In fact, a little thought will