Who Needs Emotions? The Brain Meets the Robot

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be to vocalize to the person to get his or her attention. If this strategy fails
over a few attempts, the level of frustration associated with this behavior
increases as its activation level decreases. This gives other competing behaviors
within the same behavior group a chance to win the competition and
become active instead. For instance, the next active behavior strategy might
be one where Kismet leans forward and wiggles its ears in an attentiongrabbing
display. If this also fails, the prolonged absence of social interaction
will eventually elicit sorrow, which encourages sympathy responses from
people, a third strategy to get attention from people to satiate the social drive.
CONCLUSION
In this chapter, we have explored the benefits that emotive and cognitive
aspects bring to the design of autonomous robots that operate in complex
and uncertain environments and perform in cooperation with people. Our
examples highlight how Kismet’s emotive system works intimately with its
cognitive system to improve its overall performance. Although the cognitive
system is designed with a variety of mechanisms to support attention,
behavior arbitration, and motor expression (see “Overview of the Cognitive
System”), these cognitive mechanisms are enhanced by emotion-inspired
mechanisms that further improve Kismet’s communicative effectiveness, its
ability to focus its attention on relevant stimuli despite distractions, and its
ability to prioritize goals to promote flexible behavior that is suitably opportunistic
when it can afford to be persistent when it needs to be.
What about the external expression of emotion? Even if one were to
accept the internal regulatory and biasing benefits of emotion-inspired mechanisms,
do these need to be accompanied by social–emotive expression?
Granted, it is certainly possible to use other information-based displays to
reveal the internal state of robots: flashing lights, laser pointers, graphics,
etc. However, people would have to learn how to decipher such displays to
understand what they mean. Furthermore, information-based displays fail
to leverage from the socio-affective impact and intuitive meaning that biological
signals have for people.
Kismet’s emotive system implements the style and personality of the
robot, encoding and conveying its attitudes and behavioral inclinations toward
the events it encounters. People constantly observe Kismet’s behavior
and its manner of expression to infer its internal state as they interact with
it. They use these expressive cues as feedback to infer whether the robot
understood them, its attitude about the interaction, whether they are engaging
the robot appropriately, whether the robot is responding appropriately
to them, etc. This helps the person form a useful mental model for the