Who Needs Emotions? The Brain Meets the Robot

80 brains
We conclude by discussing some recent results on positive emotions
such as attachment, and by listing a set of rules that have emerged from
the neuroscience of fear. These rules can inform future attempts at implementing
fear and other emotions in artifacts such as robots.
The approach presented here is a straightforward experimental approach
to emotion, which avoided vague concepts such as “affect,” “hedonic
tone,” and “emotional feelings.” It is important that the mistakes
of the past not be made again, and that we expand from this foundation
into broader aspects of mind and behavior.
The current wave of interest in the neural bases of emotion raises
the question of why emotion was overlooked for so long. We will consider
this question before examining what has been learned about emotional circuits
because interest in emotion has now reached other research domains,
such as computer science and robotics. These new areas of investigation are
now faced with the same challenges that faced neuroscience a few decades
ago.
WHY DID INTEREST IN EMOTION WANE?
As soon as pioneering brain researchers in the late 19th century identified
regions of the brain involved in sensory perception and movement control (the
neocortex), William James (1890) asked whether emotions might be explained
in terms of these functions or whether emotion was the business of a separate,
yet undiscovered brain system. Being a pragmatist, he proposed a theory
of emotion based solely on functions of sensory and motor systems. Specifically,
he argued that emotionally arousing stimuli are perceived by the sensory
cortex, which activates the motor cortex to produce bodily responses
appropriate to the emotionally arousing stimulus. Emotional feelings then
result when the sensory cortex perceives the sensations that accompany bodily
responses. Since different emotions involve different bodily responses, they
have different sensory signatures and thus feel different. The essence of James’
theory is captured by his conclusion that we do not run from a bear because
we feel afraid but, instead, we feel afraid because we run. James’ theory was
quickly refuted by research showing that complete removal of the neocortex
failed to disrupt the expression of emotional responses elicited by sensory
stimuli; sensory and motor cortex could therefore not be the key.
During the first half of the 20th century, brain researchers were immensely
interested in the brain mechanisms of emotional behavior. Some