Creating New Informational Primitives in Minds and Machines - Computers and Creativity - page 399

with nervous systems are cybernetic, goal-seeking percept-action systems (Arbib
1989 ,Powers 1973 , Sommerhoff 1974 , Cariani 2011 , Boden 2006 ,Pickering 2010 ,
McCulloch 1965 ,Rose 2006 ). Nervous systems evolved in motile animals in order
to better coordinate effective action in rapidly changing situations. Lineages of an-
imals whose nervous systems enhanced survival to reproduction persisted, whereas
those with less effective steering mechanisms tended to perish. Like the adaptive
devices discussed above in Sect. 15.3 , animals have sensory systems that register
interactions with the external world, and motor systems that influence events in
the world. They have coordinative sensorimotor linkages with varying degrees of
complexity, from automatic reflexes to heavily deliberated actions. Brains have em-
bedded goal systems that enforce drive states that steer both perception and action.
Embedded goals and steering mechanisms are what make intentional, purposive ac-
tion possible. Finally brains have reward systems that reconfigure internal circuits to
change steering functions and to build neuronal assemblies that facilitate new sen-
sory analyses, cognitive representations, affective and motivational responses, and
motor sequencing programs.
Thus globally, the brain is a goal-directed system in which the most primal goal
structures, which motivate actions such as breathing, drinking, eating, fleeing, fight-
ing, and mating, are embedded in limbic structures and dopamine-mediated reward
systems. Neural goal-seeking mechanisms steer sensory and motor thalamocortical
systems to act on system-goals by means of the basal ganglia , a large set of brain
structures that mediate connections of sensory, cognitive, and motor areas of the
cerebral cortex with other limbic goal and reward circuits (Redgrave 2007 ). The
basal ganglia facilitate amplification of goal-relevant sensory information and mo-
tor programs by releasing the relevant neuronal subpopulations from inhibition, i.e.
“disinhibition”.
This arrangement for steering can be thought of as a control brake on a slave
braking system; when the control brake is applied, the slave brake is released. If the
normal state of recurrent circuits with the inhibitory, slave brakes on is attenuating,
but becomes weakly amplifying when the inhibitory slave brakes themselves are
inhibited (by the basal ganglia control inputs), then those patterns of sensory, cogni-
tive, and motor activity that are relevant to the system-goals that are currently most
pressing will be the ones that will be amplified and regenerated. Neural signal regen-
eration in these weakly amplifying loops will then continue until some other set of
competing goals becomes dominant. The behavioural steering system is reminiscent
of Kilmer and McCulloch's reticular formation action selection model (Kilmer and
McCulloch 1969 ) and of Rodney Brooks' subsumption architectures (Brooks 1999 )
in that the different goals are in constant competition for control over the organism's
mode of behaviour.
15.5.3 Regenerative Loops
The basic functionalities involved in perception, coordination, and action may be
implemented by global architectures that consist of many reciprocally connected