Digital Seeds from a Virutal Core

Keith Sutherland
Why Do We Want to Open
the Black Box?

Ask any non-specialist (not to mention a hard rump of old fashioned cognitive
scientists) about the mind and chances are you will hear some version of the old
yarn ‘mind is to brain as computer software is to hardware’. Although this myth
has its origins in the science-envy that led psychology to make its Faustian pact
with the artificial intelligence industry, neuroscientists have not been entirely free
of culpability.

Greenfield pours scorn on this by outlining more recent evidence on
the modulatory role of neurotransmitters, along with a discussion of Rodolfo
Llinás’s extraordinary discovery that dendrites from the cerebellum, usually
viewed as humble one-way conduits, are themselves involved in a kind of learn-
ing process. Even without considering some of the more exotic theories about
microtubules and the cytoskeleton, neurons are exquisitely complex and it is a
serious error to represent them as simple digital switches. Also brains are inte-
grated into bodies and are subject to all manner of hormonal and visceral influ-
ences. ‘To model the brain in its entirety, one needs to model a body too’ (p. 105).

Bodies are also situated in a social and cultural milieu. Although pharmacolo-
gists normally restrict themselves to studying how, say, amphetamine increases
arousal by boosting the effect of dopamine in the brain, Greefield reports research
that shows that the same drug, the same arousal, can produce markedly different
emotions, depending on the social context. Experimental subjects who were
expecting to be given amphetamine enjoyed its effects but subjects who were
(untruthfully) told that they had been given a placebo simply felt anxious.

reenfield points out that
vision is a highly active system, replete with top-down feedback loops and even
goes so far as to endorse Llinás’s radical view that there is no essential differ-
ence between waking and sleeping. In both cases the brain actively constructs
the world — waking is just dreaming with the eyes open and without sensory
constraints.

eeing as no-one has the faintest idea how human memory works, the tempta-
tion has been to borrow words like ‘store’, ‘retrieve’ and ‘memory trace’ from the
computer science literature. But there is no proven parallel between human and
computer memory. Computer memory is localised whereas, as Wilder Penfield
famously discovered, there is no reliable correlation between the cortical area
stimulated and the specific memory evoked.

Does the elaborate processing required to
extract results from the raw scanning data not cast serious doubts on the validity
of the findings? (Uttal, 2001).

Greenfield proffers her own dynamic theory as a candidate, according to which
transient assemblies of tens of millions of brain cells — distributed across many
different brain areas — compete with each other to generate moments of con-
sciousness.4 According to Greenfield, consciousness is not a ‘magic switch’,
rather a dimmer switch, a continuum. There is no sudden transition (in phylogeny
or ontogeny) to sentience, only a question of degree.

She uses evidence from the incremental ablation of consciousness under anaes-
thetics to support her theory, speculating that deeper levels of anaesthesia are
associated with smaller neuronal assemblies. To Greenfield, ‘increased’ con-
sciousness means larger, more complex neuronal assemblies, in which sensory
input, emotion, rationality, and the richness of past experience all combine. This
leads her to conclude that dreaming and ‘being trapped in the present moment’ are
lower forms. However, some of our most vivid experiences occur during dreams
and countless systems of esoteric philosophy value the ‘experience of the present
moment’ or the ‘pure’ (contentless) conscious event as the most highly developed
form of conscious experience. But perhaps there is no conflict here as such phi-
losophies often equate the onset of (human, linguistic) consciousness with the
Fall and seek to offer the path back to the Garden of Eden.

Greenfield cites Benjamin Libet’s discovery — a pinprick to the hand only
takes 20 milliseconds to reach the brain, but a further half second to generate con-
scious experience — as evidence for the time needed to recruit a large enough
neuronal assembly.

Thus our so-called free will is just an
epiphenomenon of deterministic brain processes. ‘If consciousness and free will
are mere illusions, where does this leave personal responsibility and accountabil-
ity?’ (p. 184).