Artificial Game Presenter Avatars · personal or classroom use is granted without fee provided that...

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Artificial Game Presenter Avatars Anthony Savidis 1,2 , Effie Karouzaki 1 1 Institute of Computer Science, FORTH 2 Department of Computer Science, University of Crete {as,karuzaki}@ics.forth.gr ABSTRACT We propose artificial game presenter avatars embodying affective behavior to draw player-adapted social feedback during gameplay and introducing extra challenges to players called mini games, such as hangman and random card selection. The avatar’s AI was designed as an extension of the traditional sense-think-act loop of game characters to address the need for emotional reflection and adaptive reaction. We provide a cartoon-like 2d delivery for our avatar, however, one could support alternative approaches for rendering and animation. 1. INTRODUCTION Our work is motivated by the popularity of television game shows and the lack of an analogy in the domain of computer-based entertainment. Technically, all games played in such shows are multiplayer computer games with a technological setup amplifying social interaction. Essentially, the game presenter provokes social interaction to keep the players and the audience constantly motivated and alerted about the game progress. For this purpose, a show presenter relies on player profiles, current challenge and previous performance to provide feedback commonly involving humor, reward, sympathy, surprise, disappointment, enthusiasm, agony and anticipation. Clearly, presenters display an affective behavior. In this context, we have developed an artificial game-presenter avatar, named Amby, as a software system that can be incorporated in turn-taking multiplayer games. Amby was created to support the concept of multiplayer computer games hosted by artificial avatars as illustrated within Figure 1, top left. The top right part of Figure 1 shows how Amby has been incorporated within a pervasive board-game named Four Elements 1 [2] with an overall physical setup inspired from game shows. To our knowledge there is no similar work proposing or implementing the idea of an artificial 1 A video of the Four Elements game is available from: http://www.ics.forth.gr/hci/files/plang/BoardGameVide(High%2 0res).wmv and a video of Amby in a play session is available from: http://www.ics.forth.gr/hci/files/plang/AmbyVideo.avi Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Artificial Game Presenter Primary Game Terrain Roundtable Player Positions Enthusiasm, Positive surprise Artificial Game Presenter Primary Game Terrain Roundtable Player Positions Artificial Game Presenter Primary Game Terrain Roundtable Player Positions Enthusiasm, Positive surprise Figure 1. The concept of computer games with artificial presenter avatars and its instantiation with our avatar. Artificial Avatars Affective Computing Game Characters Adaptive Interaction Focus Area Artificial Avatars Affective Computing Game Characters Adaptive Interaction Artificial Avatars Affective Computing Game Characters Adaptive Interaction Focus Area 1.Sense 2.Reflect 3.Think 4.Adapt 5.React Exte rn al Stim ul i Affect ive State s Abstract Reactions Concre te Reactions Performing Actions 1.Sense 2.Reflect 3.Think 4.Adapt 5.React Exte rn al Stim ul i Affect ive State s Abstract Reactions Concre te Reactions Performing Actions Happiness Enthusiasm Disappointment Sadness Positive / Negative Anticipation Negative / Positive Anticipation Encouragement / Discouragement Calm Anger Anxiety Reassurance Encouragement / Discouragement Discouragement / Encouragement Discouragement / Encouragement Happiness Enthusiasm Disappointment Sadness Positive / Negative Anticipation Negative / Positive Anticipation Encouragement / Discouragement Calm Anger Anxiety Reassurance Encouragement / Discouragement Discouragement / Encouragement Discouragement / Encouragement Figure 2: The domain of our work (left), the enhanced behavior loop (middle) and the affective state space of our avatar (right). Permission to make digital or hard copies of part or all of this work or personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. 2009, -Oct , 2009, © ACM 2009 ISBN: 978-1-60558- - /09/ 0...$10.00 415

Transcript of Artificial Game Presenter Avatars · personal or classroom use is granted without fee provided that...

Page 1: Artificial Game Presenter Avatars · personal or classroom use is granted without fee provided that copies ... The concept of computer games with artificial presenter avatars and

Artificial Game Presenter Avatars Anthony Savidis1,2, Effie Karouzaki1

1Institute of Computer Science, FORTH

2Department of Computer Science, University of Crete

{as,karuzaki}@ics.forth.gr

ABSTRACT

We propose artificial game presenter avatars embodying affective

behavior to draw player-adapted social feedback during gameplay

and introducing extra challenges to players called mini games,

such as hangman and random card selection. The avatar’s AI was

designed as an extension of the traditional sense-think-act loop of

game characters to address the need for emotional reflection and

adaptive reaction. We provide a cartoon-like 2d delivery for our

avatar, however, one could support alternative approaches for

rendering and animation.

1. INTRODUCTION Our work is motivated by the popularity of television game shows

and the lack of an analogy in the domain of computer-based

entertainment. Technically, all games played in such shows are

multiplayer computer games with a technological setup

amplifying social interaction. Essentially, the game presenter

provokes social interaction to keep the players and the audience

constantly motivated and alerted about the game progress. For this

purpose, a show presenter relies on player profiles, current

challenge and previous performance to provide feedback

commonly involving humor, reward, sympathy, surprise,

disappointment, enthusiasm, agony and anticipation. Clearly,

presenters display an affective behavior. In this context, we have

developed an artificial game-presenter avatar, named Amby, as a

software system that can be incorporated in turn-taking

multiplayer games. Amby was created to support the concept of

multiplayer computer games hosted by artificial avatars as

illustrated within Figure 1, top left. The top right part of Figure 1

shows how Amby has been incorporated within a pervasive

board-game named Four Elements1 [2] with an overall physical

setup inspired from game shows. To our knowledge there is no

similar work proposing or implementing the idea of an artificial

1 A video of the Four Elements game is available from:

http://www.ics.forth.gr/hci/files/plang/BoardGameVide(High%2

0res).wmv and a video of Amby in a play session is available

from: http://www.ics.forth.gr/hci/files/plang/AmbyVideo.avi

Permission to make digital or hard copies of all or part of this work for

personal or classroom use is granted without fee provided that copies

are not made or distributed for profit or commercial advantage and that

copies bear this notice and the full citation on the first page. To copy

otherwise, or republish, to post on servers or to redistribute to lists,

requires prior specific permission and/or a fee.

Artificial

Game

Presenter

Primary Game

Terrain

Roundtable Player Positions

Enthusiasm,

Positive surpriseArtificial

Game

Presenter

Primary Game

Terrain

Roundtable Player Positions

Artificial

Game

Presenter

Primary Game

Terrain

Roundtable Player Positions

Enthusiasm,

Positive surprise

Figure 1. The concept of computer games with artificial presenter avatars and its instantiation with our avatar.

Artificial

Avatars

Affective

ComputingGame

Characters

Adaptive

Interaction

Focus

Area

Artificial

Avatars

Affective

ComputingGame

Characters

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Artificial

Avatars

Affective

ComputingGame

Characters

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Focus

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1.Sense

2.Reflect 3.Think

4.Adapt

5.React

External Stimuli

Affective States

Abstract Reactions

Concrete Reactions

Performing Actions

1.Sense

2.Reflect 3.Think

4.Adapt

5.React

External Stimuli

Affective States

Abstract Reactions

Concrete Reactions

Performing Actions

Happiness

Enthusiasm

Disappointment

Sadness

Positive / Negative

Anticipation

Negative / Positive

Anticipation

Encouragement /

Discouragement

Calm

Anger

AnxietyReassurance

Encouragement /

Discouragement

Discouragement /

Encouragement

Discouragement /

Encouragement

Happiness

Enthusiasm

Disappointment

Sadness

Positive / Negative

Anticipation

Negative / Positive

Anticipation

Encouragement /

Discouragement

Calm

Anger

AnxietyReassurance

Encouragement /

Discouragement

Discouragement /

Encouragement

Discouragement /

Encouragement

Figure 2: The domain of our work (left), the enhanced behavior loop (middle) and the affective state space of our avatar (right).

Permission to make digital or hard copies of part or all of this work or personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee.Ace 2009, Oct 29-Oct 31, 2009, Athens, Greece© ACM 2009 ISBN: 978-1-60558-864-3/09/10...$10.00

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Page 2: Artificial Game Presenter Avatars · personal or classroom use is granted without fee provided that copies ... The concept of computer games with artificial presenter avatars and

presenter avatar for computer-games supporting affective behavior

and player-adapted social reactions. Technically our work falls in

the intersection of the four domains depicted under Figure 2, left.

2. BEHAVIOR The behavior loop of our avatar is an improvement of the

traditional sense-think-act loop (see Figure 2, middle) for game

characters introducing reflect and adapt as two extra processing

stages. We logically split avatar reactions in two levels: (a)

abstract reactions, denoting the general reaction category; and (b)

concrete reactions, being alternative ways of specializing abstract

reactions. Comparing to the Circumplex model [1] we dropped a

few aspects (see being meaningless in a game context: (i) ‘fear’

and ‘disgust’ emotions; (ii) distinction among ‘activation’ and

‘deactivation’ (i.e. no tangible trophy); and (iii) intermediate

states for sadness like ‘guilt’ or ‘depression’ (see Figure 2, right).

The reflect process is implemented as a hybrid state transition

network with transitions involving condition expressions

(predicates). Player emotions relate to distinct affective states thus

the transition logic is affect computation. In practice, emotional

changes heavily depend on the summative effect of other game

incidents (events). For this purpose we introduced summative

variables that can be involved in transition predicates, together

with memory variables, normally recording game events.

3. ARCHITECTURE The overall architecture is illustrated under Figure 3, left part,

showing the split amongst the decision rules categories (such as

think and reflect), as well as the various external libraries

deployed encompassing data required for the implementation of

the avatar physical reactions (such as images, audio files and

expression animations). Also, the dual role of the avatar User

Interface is outlined: (a) as a server of “reaction” requests coming

from the avatar AI component; and (b) as a server of game hosting

requests coming directly from the game to support inventory,

player display, turn taking functionality, and mini games. All

communication between the avatar and the AI module or the game

core takes places over the network custom protocols. A couple of

scenes from hangman game sessions are shown under Figure 3,

right part, illustrating the respective emotion states.

4. SUMMARY Our work is motivated by the huge popularity of television game

shows and the key role of the presenter towards their success. For

this purpose we introduced the notion of an artificial game-

presenter avatar and we identified affective adaptive behavior to

be the most important feature towards this direction. Clearly,

anthropomorphism and quality of representation are other highly-

critical dimensions that we do not address in the context of our

work. To accomplish affective behavior we have implemented a

scalable architecture relying on adaptation-processing loops. To

our knowledge no earlier work proposed computer-games as

socially-stimulating experiences motivating social peers to watch

play sessions as in typical television game shows. In making the

artificial intelligence core of our avatar we adopted a decision

specification language we developed earlier named DMSL [3],

while we have embedded its interpreter as part of the avatar

implementation system.

The primary extensions we introduced to the basic sense-think-act

behavior processing concerned: (a) a reflect stage to derive

players emotions (affective processing); and (b) an adapt stage to

specialize avatar reactions in ways bets-fitting individual player

profiles. An extra feature we included is the on-the-fly generation

of a textual script in the form of dialogues amongst players and

the avatar. As part of our future extensions we work on the

structuring of rule libraries in ways enabling meta-rules choose

alternative avatar behavior styles such as humorous, ironic,

teasing or compassionate.

5. REFERENCES [1] J. Russell, G. Lemay (2000). Emotion Concepts. In

Handbook of Emotion, M. Lewis, M. Haviland-Jones (Eds.),

New York: Guilford Press.

[2] A. Savidis, Y. Lilis (2008). Adaptable pluggable multimodal

input with extensible accessible soft dialogues for games. In

ACM ACE 2008 Int. Conf. on Advances in Computer

Entertainment, pp. 155-158.

[3] A. Savidis, M. Antona, C. Stephanidis (2005). A Decision-

making Specification Language for Verifiable User-interface

Adaptation Logic. Journal of Software Engineering and

Knowledge Engineering, Volume 15, Issue 6 (December

2005), pp. 1063-1094.

Reflect

ru les

Th ink

ru les

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rules

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pro fil es

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Utility F unctions Exported to DMS L

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Figure 3. Software architecture of our avatar (left), and details of the User Interface component architecture (right).

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