Page 163 - Designing Sociable Robots

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144 Chapter 9

movements, and vocalize excitedly. The display is designed to attract a person’s attention.
The robot then resumes a neutral posture, perks its ears, and raises its brows in an expectant
manner. It waits in this posture for a while, giving the person time to approach before
the calling sequence resumes. The call-to-person behavior will continue to request the
display from the motor system until it is either successful and becomes deactivated, or it
becomes irrelevant.
The second task is the greet-person behavior. This behavior is relevant when the
person has just entered face-to-face interaction range. It is also relevant if the Social
Play Level Two behavior group has just become active and a person is already within
face-to-face range. The goal of the behavior is to socially acknowledge the human and to
initiate a close interaction. When active, it makes a request of the motor system to perform
the greeting display. The display involves making eye contact with the person and smiling
at them while waving the ears gently. It often immediately follows the success of the
call-to-person behavior. It is a transient response, only issued once, as its completion
signals the success of this behavior.
The third task is attentive-regard. This behavior is active when the person has already
established a good face-to-face interaction distance with the robot but remains silent. The
goal of the behavior is to visually attend to the person and to appear open to interaction. To
accomplish this, it sends a request to the motor system to hold gaze on the person, ideally
looking into the person’s eyes if the eye detector can locate them. The robot watches the
person intently and vocalizes occasionally. If the person does speak, this behavior loses the
competition to the vocal-play behavior. This behavior is viewable on the CD-ROM in
the fifth demonstration, “Visual Behaviors.”
The fourth task is vocal-play. The goal of this behavior is to carry out a proto-dialogue
with the person. It is relevant when the person is within face-to-face interaction distance
and has spoken. To perform this task successfully, the vocal-play behavior must closely
regulate turn-taking with the human. This involves a close interaction with the perceptual
system to perceive the relevant turn-taking cues from the person (i.e., that a person is present
and whether there is speech occurring), and with the motor system to send the relevant turn-
taking cues back to the person. Video demonstrations of Kismet’s “Proto-Conversations”
can be viewed on the accompanying CD-ROM.
There are four turn-taking phases this behavior must recognize and respond to. Each
state is recognized using distinct perceptual cues, and each phase involves making specific
display requests of the motor system:

• Relinquish speaking turn This phase is entered immediately after the robot finishes speak-
ing. The robot relinquishes its turn by craning its neck forward, raising its brows, and making
eye-contact (in adult humans, shifting gaze direction is sufficient, but Kismet’s display is