IVAs and Education -- Training Agents: An Architecture for Reusability -- Ask&Answer: An Educational Game Where It Pays to Endear Your Capricious Virtual Companion -- Conversational Agents/NLP -- Natural Behavior of a Listening Agent -- Providing Computer Game Characters with Conversational Abilities -- Fight, Flight, or Negotiate: Believable Strategies for Conversing Under Crisis -- Dialog Simulation for Background Characters -- IVA Architectures -- INTERFACE Toolkit: A New Tool for Building IVAs -- Autonomous Virtual Agents Learning a Cognitive Model and Evolving -- Using Real Objects to Communicate with Virtual Characters -- A Software Engineering Approach Combining Rational and Conversational Agents for the Design of Assistance Applications -- Marve: A Prototype Virtual Human Interface Framework for Studying Human-Virtual Human Interaction -- Cognition, Reasoning and Behaviour -- A Knowledge-Based Scenario Framework to Support Intelligent Planning Characters -- CAA: A Context-Sensitive Agent Architecture for Dynamic Virtual Environments -- When Emotion Does Not Mean Loss of Control -- Social Situated Agents in Virtual, Real and Mixed Reality Environments -- Do You See What Eyes See? Implementing Inattentional Blindness -- Social Causality and Responsibility: Modeling and Evaluation -- NonVerbal Communication -- Teaching Virtual Characters How to Use Body Language -- Direction of Attention Perception for Conversation Initiation in Virtual Environments -- A Model of Attention and Interest Using Gaze Behavior -- Where Do They Look? Gaze Behaviors of Multiple Users Interacting with an Embodied Conversational Agent -- Hierarchical Motion Controllers for Real-Time Autonomous Virtual Humans -- Modeling Dynamic Perceptual Attention in Complex Virtual Environments -- Storytelling/Interactive Narrative -- An Objective Character Believability Evaluation Procedure for Multi-agent Story Generation Systems -- Proactive Mediation in Plan-Based Narrative Environments -- FearNot! – An Experiment in Emergent Narrative -- Intelligent Virtual Agents in Collaborative Scenarios -- Social Intelligence -- A Conversational Agent as Museum Guide – Design and Evaluation of a Real-World Application -- Using Ontology to Establish Social Context and Support Social Reasoning -- Integrating Social Skills in Task-Oriented 3D IVA -- Emotions/Affect/Personality -- Emergent Affective and Personality Model -- Judging Laura: Perceived Qualities of a Mediated Human Versus an Embodied Agent -- The Significance of Textures for Affective Interfaces -- Levels of Representation in the Annotation of Emotion for the Specification of Expressivity in ECAs -- Extended Behavior Networks and Agent Personality: Investigating the Design of Character Stereotypes in the Game Unreal Tournament -- Evaluation and Methodology -- Direct Manipulation Like Tools for Designing Intelligent Virtual Agents -- Social Communicative Effects of a Virtual Program Guide -- Maintaining the Identity of Dynamically Embodied Agents -- The Behavior Oriented Design of an Unreal Tournament Character -- MyTutor: A Personal Tutoring Agent -- Poster Session -- Using Facial Expressions Depicting Emotions in a Human-Computer Interface Intended for People with Autism -- A Survey of Computational Emotion Research -- A Study on Generating and Matching Facial Control Point Using Radial Basis Function -- A Platform Independent Architecture for Virtual Characters and Avatars -- GAL: Towards Large Simulations with Tens of Agents -- Virtual Agents in a Simulation of an ISO-Company -- Appraisal for a Character-Based Story-World -- Evolving Emotional Behaviour for Expressive Performance of Music -- A Model of an Embodied Emotional Agent -- Agent Assistance for 3D World Navigation -- NeXuS: Delivering Perceptions to Situated Embodied Agents -- Emotion in Artificial Intelligence and Artificial Life Research: Facing Problems -- A Synthetic Agent for Mentoring Novice Programmers Within a Desktop Computer Environment -- vBroker: Agents Teaching Stock Market -- Emergence of Representational Structures in Virtual Agents.The origin of the Intelligent Virtual Agents conference dates from a successful workshop on Intelligent Virtual Environments held in Brighton at the 13th European Conference on Artificial Intelligence (ECAI'98). This workshop was followed by a second one held in Salford in Manchester in 1999. Subsequent events took place in Madrid, Spain in 2001 and Irsee, Germany in 2003 and attracted participants from both sides of the Atlantic as well as Asia. th This volume contains the proceedings of the 5 International Working Conference on Intelligent Virtual Agents, IVA 2005, held on Kos Island, Greece, September 12–14, 2005, which highlighted once again the importance and vigor of the research field. A half-day workshop under the title “Socially Competent IVA’s: We are not alone in this (virtual) world!” also took place as part of this event. IVA 2005 received 69 submissions from Europe, North and South America, Africa and Asia. The papers published here are the 26 full papers and 14 short papers presented at the conference, as well as one-page descriptions of the 15 posters and the descriptions of the featured invited talks by Prof. Justine Cassell, of Northwestern University and Prof. Kerstin Dautenhahn, of the University of Hertfordshire. We would like to thank a number of people that have contributed to the success of this conference. First of all, we thank the authors for their high-quality work and their willingness to share their ideas.