Termine unter: http://www.informatik.uni-hamburg.de/Info/Kolloquium/
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*Establishing Joint Attention with a Virtual Human*
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Prof. Dr. Ipke Wachsmuth
Universität Bielefeld
Technische Fakultät
Montag, 24. November 2008
um 17 Uhr c.t.
Vogt-Kölln-Straße 30
Konrad-Zuse-Hörsaal
Gebäude B
A foundational skill in human social interaction, joint attention is
also receiving increased interest in human-robot interaction and in
virtual humans research. Joint attention can be defined as
simultaneously allocating attention (i.e. intentionally directed
perception) to a target object as a consequence of attending to each
other's attentional states. While existing computational models mostly
deal with surface behaviors like simultaneous looking or perceptual
attention, aspects of aligning the attentional foci of the interactants
are not covered.
We (joint work with Nadine Pfeiffer-Leßmann) investigate joint attention
in a cooperative interaction scenario with the virtual human Max. The
human interlocutor meets the human-sized embodied agent face-to-face in
3D virtual reality. The human's body and gaze are picked up by Max by
use of an infrared camera system and an eye-tracker; e.g., Max can
follow the human's gaze as a basic manifestation of joint attention. The
agent's mental state is modeled in the BDI (Belief-Desire-Intention)
paradigm and serves as the origin of attention mechanisms. For
establishing joint attention, three main aspects are considered.
Firstly, the human interlocutor's focus of attention has to be inferred
from the interlocutor's overt behaviors. Secondly, the situational
context is taken into account by activation processes marking relevant
objects as salient. Thirdly, the agent itself needs to display
appropriate overt behaviors to accentuate its focus of attention and
manipulate the interlocutor's mental state.
As an indicator of the human interlocutor's focus of attention, the
human's gaze is evaluated; e.g., an object is detected as being in
human's attentional focus when it has been focused at least for a total
of 400 ms in a 600 ms time frame. In addition, pointing gestures may
serve as intentional cues. For the agent to ascribe a desire to
establish joint attention to its interlocutor, the following heuristic
is used: An object has to be focused by the human interlocutor several
times, with additional glances addressing the agent in between (triadic
intentional relation). When the activation of an object passes a
threshold and the interlocutor has shown interactive glances, the agent
asserts a belief about the interlocutor's intention and responds, e.g.,
by gazing at the same object to achieve joint attention. While attention
detection can be seen as a prerequisite for establishing joint
attention, the agent also employs pro-active mechanisms to manipulate
the interlocutor's focus of attention, e.g., by intentional gaze or
pointing gestures.
Kontakt: Prof. Dr. Christopher Habel Tel.: 428 83 2417
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Informatisches Kolloquium Hamburg
Department Informatik
Vogt-Kölln-Straße 30
22527 Hamburg
http://www.informatik.uni-hamburg.de/Info/Campus/Informatik.gif
Tel. +49 40 42883 2401
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