Who Needs Emotions? The Brain Meets the Robot

an evolutionary theory of emotion 143
is therefore a goal for action, and how the representations of these neutral
sensory stimuli are appropriate as input to such stimulus–reinforcement
learning mechanisms. (Some of these issues are considered in The Brain
and Emotion: emotion in Chapter 4, feeding in Chapter 2, drinking in Chapter
7, and sexual behavior in Chapter 8.)
This approach also does not deny that it would be possible to implement
emotions in computers and specifies what may need to be implemented
for both implicit and explicit emotions, that is, emotions with conscious
feelings. It could even be useful to implement some aspects of emotion in
computers as humans may find it more natural to then deal with computers.
However, I have summarized a theory of the evolutionary utility of
emotion, which is that emotion arises from the gene-based design of organisms
by which individual genes maximize their own survival into the next
generation by specifying the goals for flexible (arbitrary) actions. As such,
emotion arises as part of a blind search by genes to maximize their own survival,
which is the “goal” of evolution. In contrast, the goal of humandesigned
computers and robots is not to provide for survival of competing
genes but, instead, to achieve particular design goals specified by the engineer,
such as exploring new terrain and sending back pictures to earth, lifting
a heavy weight, or translating from one language to another.
Notes
The author has worked on some of the experiments described here with G. C.
Baylis, L. L. Baylis, M. J. Burton, H. C. Critchley, M. E. Hasselmo, J. Hornak, M.
Kringelbach, C. M. Leonard, F. Mora, J. O’Doherty, D. I. Perrett, M. K. Sanghera,
T. R. Scott, S. J. Thorpe, and F. A. W. Wilson; and their collaboration and helpful
discussions with or communications from M. Davies and M. S. Dawkins are sincerely
acknowledged. Some of the research described was supported by the Medical
Research Council.
1. Rewards and punishers are generally external, that is, exteroceptive, stimuli,
such as the sight, smell, and taste of food when hungry. Interoceptive stimuli, even
when produced by rewards and punishers after ingesting foods and including digestive
processes and the reduction of the drive (hunger) state, are not good reinforcers.
Some of the evidence for this is that the taste of food is an excellent reinforcer,
but placing food into the stomach is not. This important distinction is described by
Rolls (1999a).
2. Part of the basis for this is that when memories are recalled, top-down connections
into the higher perceptual and cognitive cortical areas lead to reinstatement
of activity in those areas (Treves & Rolls, 1994; Rolls & Deco, 2002), which
in turn can produce emotional states via onward connections to the orbitofrontal
cortex and amygdala (Rolls, 1999a).