Page 240 - Designing Sociable Robots

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Social Constraints on Animate Vision 221

accomplished are presented in chapter 9 and can be seen in figure 9.7. Both the current
environmental conditions (as characterized by high-level perceptual releasers), as well as
motivational factors such as emotion processes and homeostatic regulation processes,
contribute to this decision process.
Interaction of the behavior level with the social level occurs through the world, as de-
termined by the nature of the interaction between Kismet and the human. As the human
responds to Kismet, the robot’s perceptual conditions change. This can activate a different
behavior, whose goal is physically carried out by the underlying motor systems. The human
observes the robot’s ensuing response and shapes their reply accordingly.
Interaction of the behavior level with the motor skills level also occurs through the world.
For instance, if Kismet is looking for a bright toy, then the seek-toy behavior is active. This
task is passed to the underlying motor skill that carries out the search. The act of scanning
the environment brings new perceptions to Kismet’s field of view. If a toy is found, then the
seek-toy behavior is successful and released. At this point, the perceptual conditions for
engaging the toy are relevant and the engage-toy behaviors become active. Consequently,
another set of motor skills become active in order to track and smoothly pursue the toy.
This indicates a significantly higher level of interest and engagement.

12.6 Visual Behavior and Social Interplay

The social level explicitly deals with issues pertaining to having a human in the interaction
loop. As discussed previously, Kismet’s eye movements have high communicative value.
Its gaze direction indicates the locus of attention. Knowing the robot’s locus of attention
reveals what the robot currently considers to be behaviorally relevant. The robot’s degree
of engagement can also be conveyed to communicate how strongly the robot’s behavior is
organized around what it is currently looking at. If the robot’s eyes flick about from place
to place without resting, that indicates a low level of engagement, appropriate to a visual
search behavior. Prolonged fixation with smooth pursuit and orientation of the head towards
the target conveys a much greater level of engagement, suggesting that the robot’s behavior
is very strongly organized about the locus of attention. Eye movements are particularly
potent during social interactions, such as conversational turn-taking, where making and
breaking eye contact plays a role in regulating the exchange. As discussed previously, I
have modeled Kismet’s eye movements after humans, so that Kismet’s gaze may have
similar communicative value.
Eye movements are the most obvious and direct motor actions that support visual per-
ception, but they are by no means the only ones. Postural shifts and fixed action patterns
involving the entire robot also have an important role. Kismet has a number of coordi-
nated motor actions designed to deal with various limitations of Kismet’s visual perception