- seCtIon tWo: tHe BRAIn
At first, Gazzaniga also believed that consciousness had been
separated to give a ‘double conscious system’ (1992, p. 122). But
later he began to doubt this conclusion with his discovery of
what he called ‘the interpreter’, located in the left hemisphere. In
one test a picture of a chicken claw was flashed to the left hemi-
sphere and a snow scene to the right. From an array of pictures
the patient, P. S., then chose a shovel with the left hand and a
chicken with the right. When asked why he replied, ‘Oh, that’s
simple. The chicken claw goes with the chicken, and you need a
shovel to clean out the chicken shed’ (p. 124).
This kind of confabulation was common, especially in exper-
iments with emotions. If an emotionally disturbing scene was
shown to the right hemisphere, then the whole body reacted
appropriately with, for example, blushing, anxiety, or signs of
fear. When asked why, the uninformed left hemisphere always
made up some plausible excuse. When the right hemisphere
was ordered, for example, to laugh or walk, the whole body
would obey. When asked why, the patient might reply that the
experimenters were funny, or that he wanted to fetch a Coke.
The patients never said things like ‘Because I have a split brain
and you showed another picture to the other half ’.
Don’t think that confabulation is confined to neurological
patients. Arguably every explanation we give is a confabulation in
the sense that even with our two hemispheres connected, we do
not know either the neural bases of our actions or all the environ-
mental influences on them. So we have to make sense of them in terms of invented
desires, beliefs, opinions, and reasons. As psychologist Steven Pinker puts it,
The spooky part is that we have no reason to think that the baloney-
generator in the patient’s left hemisphere is behaving any differently from
ours as we make sense of the inclinations emanating from the rest of our
brains. The conscious mind – the self or soul – is a spin doctor, not the
commander in chief.
(2002, p. 43)
And unity is a crucial part of the spin doctor’s message.
Where does that leave the non-dominant hemisphere? Is it conscious? Gazzaniga
argued that only the left-hemisphere interpreter uses language, organises beliefs,
and ascribes actions and intentions to people. So only this hemisphere has what he
calls ‘high-level consciousness’. Sperry wondered whether the non-dominant hemi-
sphere has ‘a true stream of conscious awareness’ or is just an ‘automaton carried
along in a reflex or trancelike state’ – what some might call a zombie (1968, p. 731).
Further research showed that the two hemispheres have very different abilities: for
example, the left has far superior language skills and the right has better face rec-
ognition. The right hemisphere has been described as having the linguistic ability
of a three-year-old child, or the reasoning capacity of a chimpanzee. Yet we often
ascribe consciousness to young children and other animals. In those rare cases
where a person’s entire left hemisphere is destroyed or removed, we still consider
them to be conscious.
‘split-brain patients
harbor two conscious
minds in their two brain
halves’
(Koch, 2004, p. 294)
‘The same brain
may subserve many
conscious selves’
(James, 1890, i, p. 401)
2
2 5 2
2
FIGURE 6.7 • Schematic representation of displays used by
Ramachandran and Hubbard (2001) to test whether
synaesthetically induced colours lead to pop-out.
(a) A triangle of 2s is embedded in a matrix of 5s.
Non-synaesthetes found it hard to find the triangle.
Synaesthetes who saw 5s as (say) green and 2s as
red found the triangle easily. (b) A single grapheme
presented in the periphery is easy to identify but
when flanked by others becomes much harder to
detect. Synaesthetic colours (like normal colours)
can overcome this effect.