Who Needs Emotions? The Brain Meets the Robot

342 conclusions
Thus, evolution yields not only new brain regions connected to the old
but also reciprocal connections which modify those older regions. The resulting
system is not unidirectional in its operation, with lower levels simply
providing input to higher levels. Rather, there is a dynamic equilibrium
of multiple subsystems of the evolved system that continually adjust to significant
changes in each other and (more or less directly) in the world.
The following section will offer a “Jacksonian” analysis of the evolution
of brain mechanisms for vision and—via mechanisms for the visual control
and recognition of hand movements—language, rooted in a brief comparison
of frogs, rats, monkeys, and humans.
The usual caveats: (a) Frog → Rat → Monkey → Human is not an evolutionary
sequence; rather, the first three species are used as reference points
for stages in human evolution within the mammalian lineage. (b) There is
no claim that human vision is inherently better than that of other species.
The question is, rather, how it has adapted to our ecological niche. Human
vision (to say nothing of human bodies) is ill-suited to, for instance, making
a living in a pond by catching flies. We will turn to (a suitable abstraction
of) the notion of “ecological niche” when we return to our discussion of in
what senses may robots have emotions.
The relevance of vision and language to our account of the evolution of
emotion and its underlying brain mechanisms (see below, From Drives to
Feelings) is as follows:
1. We apply the term vision for the processing of retinal signals in
all these creatures. However, vision in the frog is midbraindominated
and specially adapted to a limited repertoire suitable
for species survival, whereas mammals augment these midbrain
mechanisms with a rich set of cortical mechanisms that make
possible a visual repertoire which becomes increasingly openended
as we pass from rat to monkey to human. In other words,
we see an evolutionary change in vision which is qualitative in
nature. Yet, the ancestral mechanisms remain an integral part
of the human visual system.
2. All these creatures have communication in the sense of vocal
or other motor signals that can coordinate behavior between
conspecifics. Yet, none of these communication systems forms
a language in the human sense of an open-ended system for
expressing novel as well as familiar meanings. The closest we
can come, perhaps, is the “language” of bees, but this is limited
to messages whose novelty lies in the variation of three parameters
which express the quality, heading, and distance of a food
source. We again see in human evolution a qualitative change