Page 390 - Deep Learning

Elements of a Unified Theory 373

formation, observation and discourse comprehension create a steady stream
of novel propositions, most of which are adopted as true and some subset of
which are encoded into long­term memory and hence are potentially available
for retrieval at a later time. such monotonic extensions are more automatic
than deliberate, virtually continuous and almost effortless. learning in this
sense needs no particular trigger other than the presence of information to be
encoded and a modicum of attention and motivation. The probability that the
extensions are accessed at some later time is determined by the amount of time
between encoding and recall, the amount of intervening memory decay, the
type and amount of interference that occurs between encoding and retrieval, the
semantic overlap between the original encoding and the subsequent retrieval
probe and other variables. The key point is that monotonic cognitive change is
continuous, like a mountain stream that never stops flowing. non­monotonic
changes are interruptions, local eddies, that appear here and there in the flow.

local Coherence and latent Conflict
The various monotonic extensions of a person’s knowledge base are not neces­
sarily consistent with one another. Knowledge structures are accessible only
when activated; that is, when they are relevant for the task at hand. A contra­
diction between a newly created knowledge structure and some prior struc­
ture can be discovered only if both are active at the same time. Because the size
of a person’s knowledge base is very large in relation to the size of his work­
ing memory, the probability that two representations will appear in working
memory at the same time by chance is minuscule. Capacity limitations also
prevent global coherence from being maintained by some special­purpose
process. A process that roams over all knowledge structures and inspects every
pair of them for conflicts would run for so long that multiple extensions of the
knowledge base might have occurred in the meantime, rendering the result
of such an inspection obsolete before it is delivered. Cognition operates with
local, not global, coherence.
As a consequence, a cognitive conflict can remain latent, that is, undiscov­
ered by the learner himself. The conflict might exist objectively, for an omni­
scient observer who has access to a complete printout of the person’s knowledge
base, but not subjectively, for the person himself. For example, categorization
processes might create the two categories “government spending” and “incen­
tives for businesses” without the person realizing that both can refer to the same
pot of money; skill acquisition processes might create multiple rules that match
in the same situations but recommend different, mutually exclusive actions;