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4.5 Globalist versus Localist Representations
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informative about the emotion, so that positioning an emotion on the given dimensions tells
one a lot.

4.5.12 Knowledge Representation, Action Selection and Planning in
Psi

In addition to the basic motivation/emotion architecture of Psi, which has been adopted (with
some minor changes) for use in CogPrime, Psi has a number of other aspects that are somewhat
different from their CogPrime analogues.
First of all, on the micro level, Psi represents knowledge using structures called “quads.” Each
quad is a cluster of 5 neurons containing a core neuron, and four other neurons representing
before/after and part-of/has-part relationships in regard to that core neuron. Quads are natu-
rally assembled into spatiotemporal hierarchies, though they are not required to form part of
such a structure.
Psi stores knowledge using quads arranged in three networks, which are conceptually similar
to the networks in Albus’s 4D/RCS and Arel’s DeSTIN architectures:

• A sensory network, which stores declarative knowledge: schemas representing images, ob-
jects, events and situations as hierarchical structures.
• A motor network, which contains procedural knowledge by way of hierarchical behavior
programs
• A motivational network handling demands

Perception in Psi, which is centered in the sensory network, follows principles similar to
DeSTIN (which are shared also by other systems), for instance the principle of perception as
prediction. Psi’s “HyPercept” mechanism performs hypothesis-based perception: it attempts to
predict what is there to be perceived and then attempts to verify these predictions using sen-
sation and memory. Furthermore HyPercept is intimately coupled with actions in the external
world, according to the concept of “Neisser’s perceptual cycle,” the cycle between exploration
and representation of reality. Perceptually acquired information is translated into schemas ca-
pable of guiding behaviors, and these are enacted (sometimes affecting the world in significant
ways) and in the process used to guide further perception. Imaginary perceptions are handled
via a “mental stage” analogous to CogPrime’s internal simulation world.
Action selection in Psi works based on what are called “triplets,” each of which consists of

• a sensor schema (pre-conditions, “condition schema”; like CogPrime’s “context”)
• a subsequent motor schema (action, effector; like CogPrime’s “procedure”)
• a final sensor schema (post-conditions, expectations; like an CogPrime predicate or goal)

What distinguishes these triplets from classic production rules as used in (say) Soar and
ACT-R is that the triplets may be partial (some of the three elements may be missing) and
may be uncertain. However, there seems no fundamental difference between these triplets and
CogPrime’s concept/procedure/goal triplets, at a high level; the difference lies in the underlying
knowledge representation used for the schemata, and the probabilistic logic used to represent
the implication.
The work of figuring out what schema to execute to achieve the chosen goal in the current
context is done in Psi using a combination of processes called the “Rasmussen ladder” (named

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