Who Needs Emotions? The Brain Meets the Robot

130 brains
the right value in the common currency for the competitive selection process.
Other types of behavior, such as sexual behavior, must be selected
sometimes, but probably less frequently, in order to maximize fitness (as
measured by gene transmission to the next generation). Many processes
contribute to increasing the chances that a wide set of different environmental
rewards will be chosen over a period of time, including not only needrelated
satiety mechanisms, which decrease the rewards within a dimension,
but also sensory-specific satiety mechanisms, which facilitate switching to
another reward stimulus (sometimes within and sometimes outside the same
main dimension), and attraction to novel stimuli. Finding novel stimuli rewarding
is one way that organisms are encouraged to explore the multidimensional
space in which their genes operate.
The above mechanisms can be contrasted with typical engineering design.
In the latter, the engineer defines the requisite function and then produces
special-purpose design features that enable the task to be performed. In the
case of the animal, there is a multidimensional space within which many optimizations
to increase fitness must be performed, but the fitness function is
just how successfully genes survive into the next generation. The solution is
to evolve reward–punishment systems tuned to each dimension in the environment
which can increase fitness if the animal performs the appropriate
actions. Natural selection guides evolution to find these dimensions. That is,
the design “goal” of evolution is to maximize the survival of a gene into the
next generation, and emotion is a useful adaptive feature of this design. In contrast,
in the engineering design of a robot arm, the robot does not need to tune
itself to find the goal to be performed. The contrast is between design by evolution
which is “blind” to the purpose of the animal and “seeks” to have individual
genes survive into future generations and design by a designer or engineer
who specifies the job to be performed (cf. Dawkins, 1986; Rolls & Stringer,
2000). A major distinction here is between the system designed by an engineer
to perform a particular purpose, for example a robot arm, and animals
designed by evolution where the “goal” of each gene is to replicate copies of
itself into the next generation. Emotion is useful in an animal because it is part
of the mechanism by which some genes seek to promote their own survival,
by specifying goals for actions. This is not usually the design brief for machines
designed by humans. Another contrast is that for the animal the space will be
high-dimensional, so that the most appropriate reward to be sought by current
behavior (taking into account the costs of obtaining each reward) needs
to be selected and the behavior (the operant response) most appropriate to
obtain that reward must consequently be selected, whereas the movement to
be made by the robot arm is usually specified by the design engineer.
The implication of this comparison is that operation by animals using
reward and punishment systems tuned to dimensions of the environment