The Meme Machine

224 THE MEME MACHINE
decided to act (or not), ‘you’ moved your finger and so on.
From an information-processing point of view the role of the ‘you’ is not at
all obvious. Light enters the eye and is focused on a layer of light-sensitive
cells. The output from these goes into four layers of cells in the retina which
extract edges and brightness discontinuities, enhance differences across
boundaries, change the coding of colour information from a three-receptor
system to one based on pairs of opposites, and throw away a great deal of
unnecessary detail. The part-digested information is then compressed and
passed along the optic nerve into the thalamus inside the brain. Here, different
types of information about the image are separately processed and the results
passed on to other parts of the visual cortex at the back of the brain. As the
information passes through it is at some times and places coded like a map, with
neighbouring positions corresponding to neighbouring locations in the world,
but, at other times and places, as more abstract information about shape,
movement or texture. Throughout the system there are numerous things going
on at once.
From the visual cortex, outputs go off to other parts of the brain, for example,
those dealing with language, reading, speech, object recognition and memory.
Since you know how to read, a search identities a letter ‘p’. Some of the
information goes to the motor cortex which co-ordinates action. From here a
movement such as pointing with your finger, will be pre-processed and then
coordinated with visual feedback as it happens, so that the finger ends up in line
with the ‘p’.
The details of this do not matter. The important point is that the description
that neuroscientists are building up of the way the brain works leaves no room
for a central self. There is no single line in to a central place, nor a single line
out; the whole system is massively parallel. In this description there is no need
for a ‘you’ who decided to find the ‘p’ (or not) and who started the finger
moving. The whole action inexorably created itself, given this book with its
instruction, and your brain and body.
You might think that there is still room for a central self as some kind of
informational or abstract centre rather than an actual place. There are several
theories of this kind, such as Baars’s (1997) global workspace theory. The
workspace is like a theatre with a bright spotlight on the stage; the events in the
bright spot are the only ones ‘in consciousness’. But this is only a metaphor and
can be a misleading one. If there is any sense to the idea of a spotlight, it is that
at any time some information is being attended to – or actively processed –
while other information is not. However, this focus of activity changes