Page 162 - Designing Sociable Robots

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The Behavior System 143

toy too fast to be tracked effectively, the excessive amount of motion is classified as “annoy-
ing” by the low-level visual processes. Either of these conditions will cause the annoy-stim
releaser to fire. The releaser sends activation energy to the withdraw behavior as well as
to the emotion system. This causes the distress process to become active. Once active,
the robot’s face exhibits an annoyed appearance. Distress also sends sufficient activation
to activate the withdraw behavior, and a request is made of the motor system to back away
from the offending stimulus. The primary function of this response is to send a social cue
to the human that they are offending the robot and thereby encourage the person to modify
her behavior.
The reject behavior is active when the robot is being offered an undesirable stimulus.
The affiliated emotion process is disgust. It is similar to the situation where an infant
will not accept the food it is offered. It has nothing to do with the offered stimulus being
noxious, it is simply not what the robot is after.

Level Two: The Play Behaviors

Kismet exhibits different play patterns when engaging toys versus people. Kismet will
readily track and occasionally vocalize while its attention is drawn to a colorful toy, but
it will not evoke its repertoire of envelope displays that characterize vocal play. These
proto-dialogue behaviors are reserved for interactions with people. These social cues are
not exhibited when playing with toys. The difference in the manner Kismet interacts with
people versus toys provides observable evidence that these two categories of stimuli are
distinguished by Kismet.
In this section I focus the discussion on those four behaviors within the Social Play
Level Two behavior group. This behavior group encapsulates Kismet’s engagement strate-
gies for establishing proto-dialogues during face-to-face exchanges. They finely tune the
relation between the robot and the human to support interactive games at a level where both
partners perform well.
The first engagement task is the call-to-person behavior. This behavior is relevant
when a person is in view of the robot but too far away for face-to-face exchange. The goal
of the behavior is to lure the person into face-to-face interaction range (ideally, about three
feet from the robot). To accomplish this, Kismet sends a social cue, the calling display,
directed to the person within calling range. A demonstration of this behavior is viewable
on the CD-ROM in the section titled “Social Amplification.”
The releaser affiliated with this behavior combines skin-tone with proximity measures.
It fires when the person is four to seven feet from the robot. The actual calling display is
covered in detail in chapter 10. It is evoked when the call-to-person behavior is active
and makes a request to the motor system to exhibit the display. The human observer sees
the robot orient toward him/her, crane its neck forward, wiggle its ears with large amplitude