HOW THE BRAIN MAKES POTENTIAL 179startling, way. As explained earlier, stable images are extremely rare or
non ex is tent in normal experience. Even when we are standing perfectly
still, small but rapid oscillations of the eyeball are constantly shift ing the
image on the ret ina. Experimenters have overcome this by attaching an
image to a kind of contact lens. Th e result for the participant is not a per-
fectly formed copy in the perceptual and/or cognitive system. Instead, the
very opposite happens— the image dis appears.
As Donald MacKay explained in reviewing such phenomena, “Stabili-
zation, even if it does not abolish all ret i nal signals, eliminates all covaria-
tion. If no correlated changes take place, there is nothing for analyzers of
covariation to analyze. If, then, seeing depends on the results of covaria-
tion analy sis, there will be no seeing.”^10
Mackay also explained how, by abstracting correlations from experi-
ence, rich predictability becomes available even from meager data. For
example, a blind person can discern the pattern on a manhole cover by
probing it with a cane. Every time we park a car, we can sense the posi-
tion of wheels and bumpers, even though we cannot actually see them.
In fact we take this covariation structure so much for granted that we
scarcely notice it. It only tends to become apparent in systems that have
been damaged in some way.
All this has impor tant implications for understanding potential and
individual diff erences. Th e standard view would claim that the creation
of stable images from sensory stimuli in the brain is via built-in rules,
genet ically determined. And, according to that view, brains vary in ef-
fi ciency (or some other power meta phor) from person to person because
of good or not- so- good genes. In real ity we fi nd it is informational struc-
ture that is impor tant. In environments with ever- changing structure,
the rules themselves have to be created through experience. Th e po-
tential (and intelligence) is an emergent property of the self- organized
system.
THE VISUAL BRAINWhen we turn to the brain in general, we fi nd similar princi ples at work.
Th e brain operates by abstracting deep correlational grammars, createdThis content downloaded from 139.184.14.159 on Tue, 17 Oct 2017 13:54:00 UTC