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6.4 Memory Types and Associated Cognitive Processes in CogPrime 111
CogPrime’s memory types are the declarative, procedural, sensory, and episodic memory
types that are widely discussed in cognitive neuroscience [TCO05], plus attentional memory for
allocating system resources generically, and intentional memory for allocating system resources
in a goal-directed way. Table 6.2 overviews these memory types, giving key references and indi-
cating the corresponding cognitive processes, and also indicating which of the generic patternist
cognitive dynamics each cognitive process corresponds to (pattern creation, association, etc.).
Figure 6.7 illustrates the relationships between several of the key memory types in the context
of a simple situation involving an OpenCogPrime-controlled agent in a virtual world.
In terms of patternist cognitive theory, the multiple types of memory in CogPrime should be
considered as specialized ways of storing particular types of patterns, optimized for spacetime
efficiency. The cognitive processes associated with a certain type of memory deal with creating
and recognizing patterns of the type for which the memory is specialized. While in principle all
the different sorts of pattern could be handled in a unified memory and processing architecture,
the sort of specialization used in CogPrime is necessary in order to achieve acceptable efficient
general intelligence using currently available computational resources. And as we have argued
in detail in Chapter 7, efficiency is not a side-issue but rather the essence of real-world AGI
(since as Hutter has shown, if one casts efficiency aside, arbitrary levels of general intelligence
can be achieved via a trivially simple program).
The essence of the CogPrime design lies in the way the structures and processes associated
with each type of memory are designed to work together in a closely coupled way, yielding coop-
erative intelligence going beyond what could be achieved by an architecture merely containing
the same structures and processes in separate “black boxes.”
The inter-cognitive-process interactions in OpenCog are designed so that
e conversion between different types of memory is possible, though sometimes computation-
ally costly (e.g. an item of declarative knowledge may with some effort be interpreted
procedurally or episodically, etc.)
e when a learning process concerned centrally with one type of memory encounters a situation
where it learns very slowly, it can often resolve the issue by converting some of the relevant
knowledge into a different type of memory: i.e. cognitive synergy
6.4.1 Cognitive Synergy in PLN
To put a little meat on the bones of the "cognitive synergy" idea, discussed repeatedly in prior
chapters and more extensively in latter chapters, we now elaborate a little on the role it plays
in the interaction between procedural and declarative learning.
While MOSES handles much of CogPrime’s procedural learning, and CogPrime’s internal
simulation engine handles most episodic knowledge, CogPrime’s primary tool for handling
declarative knowledge is an uncertain inference framework called Probabilistic Logic Networks
(PLN). The complexities of PLN are the topic of a lengthy technical monograph [GMIT08], and
are summarized in Chapter 34; here we will eschew most details and focus mainly on pointing
out how PLN seeks to achieve efficient inference control via integration with other cognitive
processes.
Asa logic, PLN is broadly integrative: it combines certain term logic rules with more standard
predicate logic rules, and utilizes both fuzzy truth values and a variant of imprecise probabilities
called indefinite probabilities. PLN mathematics tells how these uncertain truth values propagate
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