Personality and Believability Panel at the 2nd Workshop on Intelligent Virtual Agents (Virtual Agents 99) The Centre for Virtual Environments University of Salford, Salford, United Kingdom 13th September 1999 19990913 paolo@ai.univie.ac.at

Believability tradeoffs: BALANCE What is elicited from user vs. system capabilities Can go wrong both ways! System raises too high/complex/… expectations in users Systems places to high demands on users in terms of competence/ duration of interaction/... Slide 2, 19990913

Believability tradeoffs: EXPRESSIVITY Action expression problem (Phoebe Sengers) Convey a summary of the “story” behind a given situation, provide clues about ongoing task E.g.: local expressive behaviour by itself is insufficient for discrimination of current emotional state! (cf. action tendencies, Nico Frijda) Slide 3, 19990913

Believability tradeoffs: BELIEVABILITY vs. FIDELITY Impact of prior knowledge, “folk theories”, prejudices,… on subjective assessment of system performance Emphasis on believability allows better exploitation of available resources Emphasis on fidelity (usually) results in higher robustness and better consistency (see next slides) Slide 4, 19990913

Believability tradeoffs: ROBUSTNESS “Brittle depth” vs. “Robust shallowness” Depth (may be) required for “interestingness” Lessons from knowledge-based systems design Semantic vs. Architectonic Space (Nancy Kaplan) Capitalize on ambiguities/under-determination Leave space for multiple interpretation by users Symmetric requirements for system: Ability to make multiple/different interpretations/appraisals Meta-reasoning Slide 5, 19990913

Believability tradeoffs: CONSISTENCY Consistent behaviour over time entails predictability and facilitates recognition of “personality traits” E.g.: consistency of problem solving and action selection across different situations (difficult!?) May be achieved via an “inverse mapping” of dimensions of consistency to system lifeworld/ architecture “Big 3” (5) traits, action tendencies… Slide 6, 19990913

Believability tradeoffs: PERSISTENCE Persisting consequences of choices, actions, events “No undo” Slide 7, 19990913

SOCIA(L A)BILITIY Basic requirement for interactivity How? integration of system+user into a “bigger whole”: interactive system How? E.g. via social psychology models, such as: Power&Status (T. Kemper) Emotional Competence (C. Saarni) Seizure/relinquishment* of control at different levels Acceptance of broad classes of inputs (recognition of affordances) *(difficult/unusual for system designers) Slide 8, 19990913