I I In Development
I I In Design
Figure 1: LIDA Architecture
Working memory provides preconscious buffers as a
workspace for internal activities. Transient episodic
memory is a content-addressable associative memory
with a moderately fast decay rate. It is to be
distinguished from declarative memory, that is, long-
term associative, episodic memory. Procedural memory
is long-term memory for skills. (Franklin et al 2005)
Much of the activity within LIDA is accomplished by
codelets, small pieces of code that each performs one
specialized, simple task. Codelets often play the role of
daemons waiting for a particular type of situation to
occur and then acting as per their specialization.
Codelets in the LIDA model implement the processors
postulated by global workspace theory. Neurally they
can be thought of as cell assemblies or neuronal groups
(Edelman1987, Edelman and Tononi 2000). Various
sorts of codelets, including perceptual, attentional,
behavioral, expectational, etc., will be described below.
3. The Cognitive Cycle
The LIDA model suggests a number of more
specialized roles for feelings in cognition, all
combining to produce motivations and to facilitate
learning. Here we describe LIDA’s cognitive cycle
(Figure 2) in nine steps, emphasizing the roles played
by feelings and emotions by putting their descriptions
in italics. To aid the reader’s understanding of the
cognitive cycle, we will also carry along a running
example of its operation distinguished by a different
type font. Imagine that a teenage boy has just stepped
through a classroom door into the hall and looked left.
Another boy, a bully named Paul, is walking towards
him down the hall.
1. Perception. Sensory stimuli, external or
internal, are received and interpreted by
perception constructing the beginnings of
meaning. Note that this stage is unconscious.
a. Early perception: Input arrives through
senses. Specialized perception codelets
descend on the input. Those that find
features relevant to their specialty activate
appropriate nodes in the slipnet (a semantic
net with activation).
b. Chunk perception: Activation passes from
node to node in the slipnet. The slipnet
stabilizes, bringing about the convergence
(binding) of streams from different senses
and chunking bits of meaning into larger
chunks. These larger chunks, represented
by meaning nodes in the slipnet, constitute