Consciousness

ACtIVItY 6.2

Split-brain twins

Ask for two volunteers: one to play the role of a

disconnected left hemisphere (LH) and the other to

play the right (RH). Ask them to sit close together on a

bench or table. You might like to put a sticker on each,

labelling them as LH and RH. To reduce confusion we’ll

assume for this explanation that LH is female and RH

is male.

LH sits on her left hand; her right hand is free to

move. RH sits on his right hand; his left hand is

free to move. Their two free arms now approximate

to those of a normal person. RH cannot speak

(although we will assume that he can understand

simple verbal instructions). You might like to tape his

mouth over, making sure the tape will not hurt when

removed.

Perhaps the best use we can make of the mereolog-
ical fallacy is to notice whenever people attribute
consciousness to parts of a human being and ask
ourselves whether this is really what they intended.

AMNESIA

‘What year is this, Mr G.?’ asked the neurologist and
author Oliver Sacks (1985, p. 25).

‘Forty-five, man’, his patient replied. ‘What do you
mean? We’ve won the war [. . .]. There are great times
ahead.’

‘And you, Jimmie, how old would you be?’

‘Why, I guess I’m nineteen, Doc.’

Sacks then had an impulse for which he never forgave
himself. He took a mirror and showed the 49-year-old
grey-haired man his own face. Jimmie G. became
frantic, gripping the sides of his chair and demanding
to know what was going on. Sacks led him quietly to
the window where he saw some kids playing baseball
outside. Jimmie G. started to smile and Sacks stole
away. When he returned a few minutes later, Jimmie
greeted him as a complete stranger.

Jimmie G. had Korsakoff ’s syndrome, and nothing
can be done to restore memory in such cases. Jim-
mie first lost his ability to form new long-term mem-
ories (anterograde amnesia), and then began to lose
his long-term memory for past events (retrograde
amnesia). Jimmie’s amnesia was ‘a pit into which
everything, every experience, every event, would
fathomlessly drop, a bottomless memory-hole that
would engulf the whole world’ (Sacks, 1985, p. 35).

This is not, however, a complete loss of all mem-
ory. Classical conditioning remains unimpaired,
so that patients with Korsakoff ’s easily learn to
blink to a sound if it is paired with a puff to the
eye; to associate certain smells with lunchtime; or
to respond to a given visitor with pleasure, even if
they claim never to have seen that person before.
Procedural learning also remains intact. Not only
do people with amnesia often retain such skills as
driving a car or typing, they can learn new ones.
They might, for example, learn to mirror-read but
be unable to remember the words they read, and
even deny ever having learned the skill; or they
might improve at playing a computer game with-
out remembering they have played it before. They

FIGURE 6.11 • Experiment 1: RH puts his free left hand in the bag

and feels the object. When you ask what he feels,

only LH can speak.

Now you can try any of the split-brain experiments

described in this chapter. Here are just two examples.

1 You will need a large carrier bag or a pillow case

containing several small objects (e.g. pen, shoe,

book, bottle).

Out of sight of LH, show RH a drawing of one of your

objects. Ask him ‘What can you see?’ Only LH can

speak and she did not see the drawing. Press her to