176 HOW THE BRAIN MAKES POTENTIALJoseph Lappin and Warren Craft also suggest that structure has to
mean spatial relations among points emanating from a light source. Th ey
showed that it is the change of these relations over time—in the course of
motion— that reveals the structure within and between features.^8 A
simple illustration is the way that integration of slightly diff er ent images
from our two eyes depends on abstracting the spatiotemporal correla-
tions between them.
Th e associations are informative because they permit one changing
aspect or variable to be predicted from one or more others, as when we
predict the presence of a whole dog merely from a tail sticking out from
behind a sofa. Deeper, or “higher- order,” structure is pres ent when such
associations extend to three or more variables— the strength of associa-
tion between any two variables is dependent on the values of others. Th e
variables, that is, interact.
Th ese interactions are analogous with those occurring between signal-
ing proteins, TFs, noncoding RNAs, and so on, as explained in chapter 4.
Likewise, the interactions among morphogens have been shown to guide
cell diff erentiation and motility in development. Th ose interactions can
furnish information about future states and how to respond now. Only
FIGURE 6.1
A sequence of stills from a point- light walker. Volunteers fi nd the images unrecogniz-
able when presented individually on a computer screen. But pre sen ta tion as a se-
quence at normal speed evokes almost immediate recognition of a person walking.This content downloaded from 139.184.14.159 on Tue, 17 Oct 2017 13:54:00 UTChttp://www.ebook3000.com