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154 Socially Intelligent Agentssion [12] or vocal expression [10, 5] to be very useful in mapping Kismet’semotive states to its face actuators and its articulatory-based speech synthesizer.Results from various forced-choice and similarity studies suggest thatKismet’s emotive facial expressions and vocal expressions are readable.Furthermore, we have learned that artistic insights complement these scientificfindings in very important ways. A number of animation guidelinesand techniques have been developed for achieving life-like, believable, andcompelling animation [13, 11]. These rules of thumb are designed to createbehavior that is rich and interesting, yet easily understandable to the humanobserver. For instance, animators take a lot of care in drawing the audience’sattention to the right place at the right time. To enhance the readability andunderstandability of Kismet’s behavior, Kismet’s expression and gaze precedeits behavioral response to make its behavior understandable and predictable tothe human who interacts with it. People naturally tend to look at what Kismetis looking at. They observe the expression on its face to see how the robot willrespond towards it. If the robot has a frightened expression, the observer isnot surprised to witness a fleeing response soon afterwards. If they are behavingtowards the robot in a way that generates a negative expression, they sooncorrect their behavior.By incorporating these scientific and artistic insights, we found that peopleintuitively and naturally use Kismet’s expressive feedback to tune their performancein the exchange. We have learned that through a process of entrainingto the robot, both the human and robot benefit: the person enjoys the easy interactionwhile the robot is able to perform effectively within its perceptual,computational, and behavioral limits. Ultimately, these cues will allow humansto improve the quality of their instruction. For instance, human-robotentrainment can be observed during turn-taking interactions. They start to useshorter phrases, wait longer for the robot to respond, and more carefully watchthe robot’s turn-taking cues. The robot prompts the other for his/her turn bycraning its neck forward, raising its brows, and looking at the person’s facewhen it’s ready for him/her to speak. It will hold this posture for a few secondsuntil the person responds. Often, within a second of this display, the subjectdoes so. The robot then leans back to a neutral posture, assumes a neutral expression,and tends to shift its gaze away from the person. This cue indicatesthat the robot is about to speak. The robot typically issues one utterance, butit may issue several. Nonetheless, as the exchange proceeds, the subjects tendto wait until prompted. This allows for longer runs of clean turns before aninterruption or delay occurs in the robot-human proto-dialogue.Interpretation of Human’s Social Cues. During social exchanges, theperson sends social cues to Kismet to shape its behavior. Kismet must beable to perceive and respond to these cues appropriately. By doing so, the