Page 181 - Designing Sociable Robots

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162 Chapter 10

emphasis. Each subsystem serves a different facial function. The emotive facial expression
subsystem is responsible for generating expressions that convey the robot’s current moti-
vational state. Recall that the control of facial displays and behavior was partially covered
in chapter 9.
The lip synchronization and facial emphasis system is responsible for coordinating lips,
jaw,andtherestofthefacewithspeech.Thelipsaresynchronizedwiththespokenphonemes
as the rest of the face lends coordinated emphasis. See chapter 11 for the details of how
Kismet’s lip synchronization and facial emphasis system is implemented.
The facial display and behavior subsystem is responsible for postural displays of the
face (such as raising the brows at the end of a speaking turn), animated facial gestures
(such as exuberantly wiggling the ears in an attention grabbing display), and behavioral
responses (such as flinching in response to a threatening stimulus). Taken as a whole,
the facial display system encompasses all those facial behaviors not directly generated by
the emotional system. Currently, they are modeled as simple routines that are evoked by the
motor skills system (as presented in chapter 9) for a specified amount of time and then
released (see table 10.1). The motor skills system handles the coordination of these facial

Table 10.1
A summary of Kismet’s facial displays.

Stereotyped Display Description
Sleep and Wake-up Display Associated with the behavioral response of going to “sleep” and “waking up.”
Grimace and Flinch Display Associated with the fear response. The eyes close, the ears cover and are
lowered, the mouth frowns. It is evoked in conjunction with the flee
behavioral response.
Calling Display Associated with the calling behavior. It is a stereotyped movement
designed to get people’s attention and encourage them to approach
the robot. The ears waggle exuberantly (causing significant noise),
the lips have slight smile. It includes a forward postural shift
and head/eye orientation to the person. If the eye-detector can
find the eyes, the robot makes eye contact with the person.
The robot also vocalizes with an aroused affect. The desired
impression is for the targeted person to interpret the display as the robot
calling to them.
Greet Display A stereotyped response involving a smile and small waggling of the ears.
Raise Brows Display A social cue used to signal the end of the robot’s turn
in vocal proto-dialog. It is used whenever the robot should look expectant to
prompt the human to respond. If the eyes are found, the robot makes
eye-contact with the person
Perk Ears Reflex A social feedback cue whenever the robot hears and sound. It is
used as a little acknowledgement that the robot heard the person
say something.
Blink Reflex A social cue often used when the robot has finished its speaking turn.
It is often accompanied by a gaze shift away from the listener.
Startle Reflex A reflex in response to a looming stimulus. The mouth opens, the lips
are rounded, the ears perk, the eyes widen, and the eyebrows elevate.