Consciousness

• 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.