Page 79 - Biomimetics : Biologically Inspired Technologies
P. 79

Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c003 Final Proof page 65 21.9.2005 11:40pm




                    Mechanization of Cognition                                                   65

                    or action sequences are triggered instantly each time a lexicon confabulation operation yields a
                    single active symbol (i.e., a decisive conclusion). As discussed in Appendix, this is the conclusion–
                    action principle of the theory. The action(s) automatically triggered by the winning symbol can be
                    of many characters. They can be immediate postural goal outputs that are sent down the spinal cord
                    to motor nuclei and the cerebellum, they can be immediate lexicon operation commands, they can
                    be immediate knowledge base operation commands, or they can be candidate actions (cortically
                    proposed thoughts and movements) which must first be sent to the basal ganglia for evaluation and
                    approval before they are executed.
                      The main advantage of confabulation-based cognition over traditional programmed computing
                    (formal computer programs, rule-based systems, etc.) is a much greater capacity for handling novel
                    arrangements of individually familiar objects. Programmed computing must essentially have a
                    predefined plan for dealing with every situation that is to be handled. For example, a plan for
                    breaking up a complicated ensemble of problems into isolated, disconnected sub-problems, so that
                    each can be handled in a predefined way. Unfortunately, in most real-world situations, this
                    approach fails badly because complicated real-world situations inevitably have unanticipatable
                    interrelations between their elements that disallow pre-defined decompositions. By virtue of their
                    huge stores of general-purpose and low-level knowledge, confabulation-based systems are inher-
                    ently able to take novel external context into account as each individual conclusion (or ensemble of
                    conclusions — if mutual solution constraints are to be honored — see the discussion of consensus
                    building in Section 3.3) is addressed. Confabulation-based systems can also adapt existing action
                    plans (e.g., by replacing specific elements of a stored plan with similar substitutions which are
                    relevant to the current situation) to fit novel circumstances. They do not typically run out of things
                    to try and, instead, tend to press on and do the best they can, given what they know. If a particular
                    approach yields no conclusion, other approaches are typically immediately launched. Yet, because
                    actions are triggered each time a conclusion is reached, almost all behavioral sequences are
                    dramatically novel. Also, each new experience can (with occasional help from a human educator)
                    be added to the knowledge base to further enlarge the system’s future repertoire.
                      More could be said regarding the benefits of the confabulation approach. However, the remain-
                    ing sections of this chapter present more concrete examples of this. The nature of cognition is very
                    different from that of computing. So much depends upon designing clever architectures of lexicons
                    and knowledge bases and upon using clever, highly threaded, but very simple, thought processes to
                    control these architectures. Since the information processing control which must be exerted at each
                    stage of an action process is triggered by the current cognitive world state (the collection of all
                    decisive confabulation conclusions that are active, or accessible from working memory, at that
                    moment), cognition has no need for ‘‘computer programs’’ or ‘‘software.’’ In effect, the conclusion
                    of each ‘‘cognitive microprogram’’ (lowest level action sequence) is a GOTO statement. There is no
                    overall program flow defined. Just action sequences completing and then triggering subsequent
                    action sequences (in a pattern that almost never exactly repeats). Things happen as they happen,
                    with no master program controller involved or needed (although a number of subcortical brain
                    structures can execute ‘‘interrupts’’ when certain conditions occur). This brain operating system (or
                    lack thereof, depending on your point of view) seems like an invitation to disaster. However,
                    beyond possible conflicting commands to the same action (movement or thought) resource (which
                    are impossible by design! — see Appendix Section 3.A.2), very little can go wrong.


                                             3.3  LANGUAGE COGNITION


                    This section discusses the use of confabulation for representing and generating language. This
                    application arena is the most developed, and yet is transparently crude and primitive. An enormous
                    amount of work needs to be done in language. The hope of this section is to illustrate how promising
                    this research direction is.
   74   75   76   77   78   79   80   81   82   83   84