Semi-Autonomous Avatars in World of Minds

A Case Study of AI-based Game Design

ACE 2008 Yokohama, Japan

Thursday, Dec 4, D1, 9.00

Mirjam Palosaari EladhariGotland University, Sweden

Michael MateasUniversity of California, Santa Cruz, USA

Introduction

Någonting om mig – doktorand på hgo (via teeside, CS + mathematics), tidigare spelprogrammerare, bg även littvet&beteendevetenskap.

Detta, exempel på ai driven spel design forskningEIS labbet i University of California SC. (MM)

- handuppräckning: mud. Ultima online. EQ. WoW? CRPGs? TTRPGs?

Characters in MMOs

• Majority of characters in MMORPGs are player characters/avatars.

• Most character interaction take place between avatars.

• NPC’s in MMORPGs mainly give quests, sell items or give information about the world.

Round and Flat

• A flat character consist of only a few traits and usually have a single, static aim, transparent to the audience.

• A round character is complex and capable of contradiction, surprise and change. Round characters have a multitude of contradictory traits.

(Forster, Aspects of the Novel, 1927)

Chatman on Round Characters

“Round characters […] possess a variety of traits, some of them conflicting or even contradictory [...] We remember them as real people. They seem strangely familiar. Like real-life friends and enemies it is hard to describe what they are exactly like. “(Chatman,Story and Discourse, 1978)

In MMORPGs, the player characters ARE real

Round and Flat

• A flat character consist of only a few traits and usually have a single, static aim, transparent to the audience.

• A round character is complex and capable of contradiction, surprise and change. Round characters have a multitude of contradictory traits.

(Forster, Aspects of the Novel, 1927)

NPCs

Avatars

Where MMO’s fail

Despite the focus on player-to-player interaction, current MMORPG designs fail to provide explicit support for helping players to roleplay and fail to incorporate such social interaction and roleplay into the game mechanics themselves.

Goal

• To develop an AI-based game mechanic that brings round characters into MMORPGs to support the player in roleplaying through their avatar.

• Find ways to utilize the richness of the present human intelligence in virtual game worlds and via, the right triggers, enrich the game experience in terms of characterdriven drama woven into the virtual world through its rulesystem.

Outline and summaryOne of the most exciting possibilities in game AI research is for AI to open up new game design possibilities. New AI will suggest new design possibilities while design will push back on AI requirements. This paper provides:

• A concrete case study of AI-centric game design, specifically describing how AI can be powerfully and effectively used in an MMORPG design.

• The Mind Module, a technical framework for modeling personality and emotion for both player and non-player characters.

• The World of Minds (WoM), an MMORPG that employs an AI-based game mechanic designed around the MM.

• Lessons learned from a paper prototype playtest of the mechanic.

Mind Module

overview

Mind Module (MM) Overview• a semi-autonomous agent architecture

• built to be used in a multiplayer environment as a part of the player's avatar.

• The MM models the avatar's personality as a collection of traits inspired by the FFM

• maintains dynamic emotion state as a function of interactions with objects in the environment and trait values, and summarizes the avatar's current emotional state as an inner and outer mood

• Spreading Activation Network (SAN)

Deconstruction and reconstruction

• In psychlogy and neuropsychology the complexity of the human mind is made more comprehensible by deconstruction into subsystems.

• As builders of virtual humans we need to reconstruct agents that can function in way that is believable and useful to the users in the contexts and systems we devise.

Node types

Weighted network of interconnected nodes

Two-dimensional affect plane

• Emotions: brief and focused (ie. directed at an intentional object) disposition

• Sentiments: permanent and focused disposition• Mood: brief and global disposition• Personality: permanent and global disposition

Personality

• Plethora of personality theories; psychoanalytic, behaviorist, cognitive and biophysiological theories.

• Trait theory pioneered by Allport (1930ies) where the most prominent personality assessment is called the Five Factor Model.

• (also used by Guoliang, Klesen, Khirsagar, El Jed, etc)

Five Factor Model

NEO PI-R (also called OCEAN)

Personality Trait Nodes

Defines how you ”are”.

Traits: OCEAN model (Big five)

Emotions in MMEmotion Weight to

Inner Mood

Weight to Outer Mood

Amusement +2

Interest Excitement +1.5

Enjoyment/Joy +2 +2

Relief +1.5 +1.5

Satisfaction +2

Surprise +1.5

Confusion -1.5

Distress/Anguish -2 -1.5

Fear/Terror -2

Anger -2

Shame/Humiliation -1.5

Sadness -2

Guilt -1.5

13 ”basic emotions”, common to primates, as described by Ekman, Tomkins, Nathansson

Emotion Nodes

Define how you feel right now

13

Mood

In everyday sense:An overall state or quality of feeling at a particular time

Changes slower than emotionsTemporaryHighly contextualLingers even if the context changesBecomes part of the next contextIndividual – ”same” type of event result in differents moods for different people.

Moods

private, inner mood

extroverted side of the mood, how the character emotionally is relating to the game world and to other characters.

Inner and Outer Mood• The inner mood is the private sense of harmony that can be

present even if the character is in an environment where events lead to a parallel mood of annoyance.

• The nature of the outer mood is social, and as such tied to emotions that are typically not only directed towards another entity but also often expressed toward an entity, such as anger or amusement.

• The two scales for the mood nodes open up the possibility of more complex states of mind than a single binary axis of moods that cancel each other out.

Mood

Define how you feel today

We interpret the moods of people around us, and choose how to act accordingly

Sentiments – Emotional attachements

• MM allows several sentiments ie, of different emotions, to be attached toward an other entity, thus creating a compound set of sentiment.

• emergent sentiments origin from interactions with other entities in the world, thus creating emotional memories.

• authored sentiment sets have certain pre-set combinations. For example ``infatuation" is a combination of interest/excitement/amusement and joy toward another character.

Player might realize it is a good idea to RUN!

Sentiment

Define how you generally feel about specific things

An emotional disposition towards a specific object or class of objects.

Node types

Weighted network of interconnected nodes

MM Summary

• The MM thus provides the player with information about the avatars feelings toward other entities in the world.

• Proximity to objects or characters affect the emotions, and thus the mood of an avatar, functioning as information the player can use to form an agenda for game play.

World of Minds Game Play

World of Minds Summary

• Prototype mutiplayer game world where the personalities of the inhabitants are the base for the game mechanics.

• When interacting with other characters, the action potential depend upon the player character's current mood and personality

Basic Game Play of WoM

Players need to defeat physical manifestations of negative mental states by using - Spells - Affective actions

The spells available to the character depends on personality

The affective actions available to the character depends on the current mood.

Spells and mind energy

• Spells cost Mind Energy to use (”mana”)• Attacks reduce Mind Resistanse (”health”)

• The amount of Mind Energy is tied to Outer Mood

• The amount of Mind Resistanse is tied to Inner Mood

Fluctuations of Energy and Resistanse

Affective actions and Mood

• players can affect each other's moods by using affective actions (AAs).

• AAs are actively chosen by the players

•the AA ``Comfort" can be used successfully on targets that have an active emotion node of Sadness, but only if the player's own avatar is not in the area of Furious on the mood matrix.

•If the AA Comfort is used successfully the values of the emotion nodes Sadness and Anguish of the target are diminished, which in turn affects the mood of the character.

Mood manipulation

• Current mood affects:– Regeneration of Energy and Mana– The range of availiable current actions

Thus, by affecting the mood of a another character the action potential of that character is changed.

Mood, Spells and Resistanse

How a sentiment and/or a manifestaion is born in WoM

Playtest

Playtest Research QuestionsThe playtest was designed to elicit design feedback from players on three different

questions:

1) During gameplay, are players able to "reverse engineer" the MM to build a mental model of how to manipulate emotional state to achieve gameplay goals? (For any successful game design, players must be able to build a model of the mechanics that allow them to successfully interact with the game.)

2) Understand the player's theory of how traits relate to MM state and gameplay in order to gather new design ideas for how traits might influence emotional state and gameplay.

3) How do the players perceive the relationship between the emotional state maintained by the MM and the game mechanics and interaction options that depend on that state?

Approach

Evaluation of the game design via a paper prototype

During the play tests, the test leader walks individual players through a paper simulation of several scenarios. Players are asked to think aloud while playing the game; additionally, the test leader stops the game at several points and conducts interviews.

(User-Centered Design, where the user's experience is a main driver for design, Rapid prototype and playtesting)

• Ten players individually went through five game mastered scenarios where her avatar had a mind, represented by the character sheet.

For each playtest, the participant:

• Filled in a short (less than ten questions) survey on demographic data and previous gaming experience.

• Took the IPIP-NEO Personality test and emailed the results to the test leader.

• Filled in a short survey about their experience taking the personality test and their opinions about the use of personality traits for avatar creation.

• Participated in the playtest, which took between 1 and 1.5 hours. Each playtest session consisted of playing five scenarios, and answering questions in two interviews, one in the middle, and one at the end of the playtest. Each session was videotaped.

• Filled in two more short surveys, one focused on sentiment objects, and the other on general impressions of the experience.

Playtest• During the five scenarios, the player was guided through using the main categories of actions in the

game including : – affective actions– navigation in a landscape of sentiment objects– mind magic spells.

• Using the character sheet the test leader updated the state of mind of the avatar and NPCs, showing the player the effect of her actions in the game in terms of fluctuations in emotions, mood, mind energy and mind resistance.

• In order to best capture player's problem-solving processes within the game, and to best understand potential areas for confusion, the players were given minimal explanations about how and what to do.

• At any point, players could access a ``help system" in order to ask any question.

• The twenty-two interview questions focused on the player's understanding of the relationship between values in the MM, effects of game actions, relationship between personality and availability of actions such as spells, etc

Data analysis

• We used the video analysis tool Transana to analyze the 15 hours of video of interviews and play sessions.

• We developed a coding scheme for potentially relevant phenomena and states of mind; this provided us with the initial framework for searching for patterns and regularities, as advocated by Miles and Huberman

Scenario 1 - Sentiments

The avatar meets the character "Gate Keeper" (GK).• Via a prewritten dialog script GK gives information

about the world the player has just arrived to. • The GK searches his bucket to give the player two

random sentiment objects. (The player represented by the avatar Mastaya got sentiments of anger toward mittens and amusement toward socks.)

• The GK asks the player to picture an unnerving scenario where she can choose which of three different objects would be most scary. (Mastaya picked garden gnomes and got a fear sentiment towards them.)

Scenario 2 - Affective Actions The avatar meets the character Teresa.

• Teresa says she is too sad to explain what affective actions (AAs) are, and asks the avatar for a hug.

• A selection of affective actions is presented to the player.

• Teresa and the avatar exchange affective actions until threshold values for emotions result in the generation of sentiment objects between the characters.

(Mastaya chose to comfort Teresa instead of hugging her. Teresa's distress and sadness decreased, and her mood improved. After a few exchanges of AAs, a threshold value for Mataya's emotion Interest/Excitement was reached and the system generated a sentiment for Mastaya of this emotion toward Teresa.)

Seven of the players chose to ``hug'' Teresa, while three of them started the chain of AA's in the scenario with using ``Comfort". The AA ``comfort" would diminish the emotions of sadness and anguish in the targeted character.

• More AA:s were revealed as the scenario continued

• Players were asked for AA:s they would like in such a scenario

• The first meeting with Teresa resulted in sentiment objects between her and the player’s character.

• Type of sentiment depenent on the exchange of affective actions

Scenario 3 - Facing the Sentiments

• The player needs to guide the avatar through an environment with sentiment objects in order to successfully accomplish a quest.

• The state of mind of the avatar changes according to which sentiments are encountered in proximity of the avatar.

(Mastaya navigated the board successfully and spent some time on the sock in order to gain amusement before moving on.)

Scenario 4 - Using Spells (and Affective Actions)

The player finds Teresa in a state of distress as she is attacked by a manifestation of Confusion.

• The player finds a spell, Laser Pen of Clarity, which reduces confusion and mental resistance in the target.

• The player is introduced to the concepts of mental energy and resistance through seeing the mind values on Theresa, the Colossus of Confusion and the players' own avatar.

• When the Colossus of Confusion is defeated, a new foe enters the scene, the Sail of Sorrow.

• When this is defeated, Teresa explains that when an emotion goes out of bounds a manifestation of that emotion is created.

• The players has been doing another scenario and comes back to Teresa. • She needs help she is attacked by a manifestation of confusion.• Here players act very in ways very different to each other for

manipulating the mood of themseleves and of Teresa

Casts spell:Trumpet irrelevant

questions and obscure answers

(++ Confusion)

Voulnerable to spell: Laser Pen of Clarity(-- Confusion)

In some of plays of this scenario Teresa, who’s personality makes her prone to depression, got so sad that a manifestation of sorrow spawned

Casts spell:Wet Net of Tears(++ Sadness)

Voulnerable to spell: Accommodate sorrow(-- Sadness)

Scenario 5 - Trait based spells The Gate Keeper gives the avatar two spells that he claims are based on the personality of the avatar.

Example: • Mastaya earns the spell "Interest/Excitement Shower", based on

the fact that her highest factor except Neuroticism is Openness. • She also learns the "Soothing Hand", which lowers fear in the

target, based on the fact that the highest value of the traits in the neuroticism factor is Anxiety.

• The Gate Keeper tells her that she will be particularly good at defeating manifestations of fear, the Terror Trolls.

Lessons from Playtest

Effects of Personality

• All players built correct mental models of at least one of the effects of personality on the MM and the game mechanics.

• All players demonstrated enough understanding of the system to be able to act in the world in such a way as to reach an emotional state they found desirable.

Examples:•Two players thought that personality affected the amount of mind energy and mind resistance.

•Three players thought that the effect of AAs on themselves and others depended on personality.

• One player thought there were personality-specific effects on mood values, hypothesizing a mapping between traits, emotions and mood.

Effects of Personality Factors

• Strong trend towards building models about extraversion. Eight of the ten players theorized about the factor.

• Agreeableness discussed by six players• Conscientiousness discussed only by one

Kita:"So, like, if you are an extrovert you might get interested and excited more easily, but you also might get distressed or anguished more easily, so each one kind of ... you know ... had an effect on your emotions."

Eric the Red:"Depending on how extroverted you are, sadness and guilt would probably move more or less as you are affected by them."

Dante: "If you are not conscientious at all [...], other people pick up on that, how [...] are they going to ask you to do anything for them?"

Extraversion and the design risks of FFM• Exraversion is a commonly described personality factor. • The GOOD thing with it is that players have an existing mental

model of it. The BAD thing is that it is often a normative model. • Players expressed worries about how their avatars would

perform in social situations if their level of extraversion is low.

Ancient Greek philosophy, Jung’s typology, etc. Also the factor most commonly studied in tests of applications for synthetic humans and conversational agents

The design goal of WoM is for personality traits to be non normative: we want a game design in which each possible combination of personality traits allows a player to success fully progress in the game.

Current design of the Mind DO weight connections between trait and emotion nodes such that it may be more difficult for an introverted avatar to perform certain social actions. However, this is balanced by having some mind magic spells only be available when the avatar is in specific mood ranges.

Personality-based SpellsIn the final scenario, each player was given two spells by the Gate

Keeper, based on their personality traits. 7 players were very positive to this while 3 players were hesitant.

These 3 are all avid players of singleplayer role playing games, where a character’s ability is based on it’s class.

Solemni:"Getting spells from personalityis a different method of choosing how your avatar interacts with the world - like a class. Not having direct control overyour class may be a difficult pill to swallow."

This highlights an important

difference between a trait-based and

class-based character system.

Trait system / class system

Since personality-based capabilities (such as mind magic spells) are not organized under classes, but instead rely on relationships between the different traits, the combination space of the possible actions for an individual avatar is larger than in a traditional class-based RPG.

Experienced players of class-based RPGs may need extra support to become comfortable with this system – a clarification of what can be expected can be necessary in future playtest, despite our principle of minimal information.

Emergent Game Play

• The scenarios in the prototype are purposefully tightly scripted, since a primary purpose of the prototype is to explore the player's understanding of the MM in the context of WoM.

• Desprite this players leveraged the MM-based game mechanics to discover alternative strategies for completing the scenarios that had not been foreseen by the designers.

Examples of emergent game playIn the fourth scenario, the players is asked to help Teresa battle the Colossus of Confusion (CoC). The

only other object in the environment is the Laser Pen of Clarity (LPC), which the player can pick up to learn the spell of the same name. This spell reduces confusion and mental resistance.

As designers, we had assumed that players would use this spell on the CoC to help Teresa.

• However, 70% of the players combined the use of AAs on Teresa with the use of their (only) spell on the CoC. Players hoped to improve Teresa's emotional state through the AAs, and thus increase her effectiveness at battling the CoC.

• 30% of the players used their LPC on Teresa, which decreases her confusion and again makes her more efficient against the CoC.

• 20% percent of the players used AAs instead of the LPC on the CoC, damaging the CoC with a lesser decrease in their mind energy than using the LPC.

• 20% ran off to the gate keeper and just so happened to learn another spell that they could go back to the CoC to use.

• Encouraging for this case of AI based game design:

• The fact that players discovered interesting, alternative strategies even in very constrained and simple scenarios validates the potential for rich and emergent gameplay in MM-based game mechanics.

Ending summary, we have described:

• The Mind Module, a semi-autonomous agent architecture.• An experimental MMORPG, World of Minds, in which the game

mechanics build upon the Mind Module's model of personality and emotion.

• In a case study of AI-based game design, we have shared lessons learned from a test of a paper prototype.

• The players were able to form and communicate mental models of the mind module and game mechanics, validating the design and giving valuable feedback for the future development of the project.

• Despite the constrained scenarios presented to test players, they discovered interesting, alternative strategies, indicating that the “mental physics" of the Mind Module may open up new game design possibilities

Thank You for listening!

Questions?

Mirjam.eladhari@hgo.se, michaelm@cs.ucsc.edu

• Slides from this point are for ref depending on questions

Mind Module - Implemented as a Spreading Activation

Network (SAN)Classes of Semantic network nodes:

Affect Nodespersonality - global and permanent

emotion - brief and focused (ie. directed at a specific object)

mood - brief and global

sentiment - permanent and focused

Spell Type Description

ES – Emotion Spell Diminishes or increase emotion in target. Reduces MR in target. Decreases ME in self. Can be AOE (Area of Effect)

MR-ME-S – Energy/Resistance Spell

Causes direct decrease or increase of ME or ME in target. Decrease ME in self. Can be AOE.

SS Sentiment Spell Set Single Sentiment in target. One of the 13 emotions. Very High Effect, Very Fast decay.

PAS – Personality Alteration Spell

Temporarily change personality trait of target. Long cool down of spell. Decrease ME in self.

SSS – Sentiment Set Spell

Set sentiment set on target. High effect, fast decay.

NEUROTICISMS-type Spell Trai

tEffect on target Effect on

SelfAnxiety

ES Cold Ripple of Fear ++ ++Fear, -MR -MEES Soothing Hand ++ --Fear, -MR -ME

AngerES Primal Fire of Fury ++ ++ Anger, -MR -MEES Cooling Cloth ++ --Anger, -MR -me

DepressionES Wet Net of Tears ++ ++Sadness, -MR -MEES Accomodate Sorrow ++ --Sadnes, -MR -ME

Self-ConsiousnessES Veil of Humiliation ++ ++Humiliation, -MR -MEES Spine of Confidence ++ --Humiliation,-MR -ME

ImmoderationES True-Sounding Accusation ++ ++Guilt, -MR -MEES Rationalise ++ --Guilt, -MR -ME

VulnerabilityES Song of Pain ++ ++Distress,-MR -MEES Dull Pain ++ --Distress -MR

trait emotion spell

Extroversion amusement Amusement shower

Agreeableness joy Joy shower

Consiouentousness satisfaction Satisfaction shower

Openness interest excitement Excitement shower

Mapping of Factors to Spells

Note: The factor Depression does not have a specific spell in paper prototype no1. In the initial scenario the player receives a spell based on the strongest factor except neuroticism. All players also receive a spell based on their highest trait in the N-factor.

Max Autonomy Min Autonomy

Non Player Character Player Character

Max Autonomy Min Autonomy

Non Player Character Player Character

Semi autonomous Avatar

Sweet spot of autonomy dependent on game design

Max Autonomy Min Autonomy

Non Player Character Player Character

Semi autonomous Avatar

Sweet spot of autonomy dependent on game design

Action Potential Constrained by state

Autonomous reactions triggered at high threshold values

in state

Autonomous reactions triggered

at low threshold values in state

The picture is called "The Mystery of the Human Head" or "The philosophical brain", and appeared in a book by the hermetic artist Robert Fludd (1574 - 1632). Utriusque cosmi maioris scilicet et minores metaphysica, physica atque technica historia was published in 1617 (Oppenheim) and came in seven volumes. In the picture Fludd visualizes the spiritual aspects of man as abiding in certain recesses of the brain. The illustration is made by Merian.

Sources:Wikipedia on Fludd JR Ritman Library Bibliotheca Philosifica Hermetica - Illustrations and informationEcho - European Cultural Heritage Online - Utriusque Cosmi maioris salicet et minoris metaphysica possible to browse page by page.Bill Heidrick's Cross References - Downloadable PDF of Utriusque Cosmi maioris salicet et minoris metaphysica

Inner and Outer Mood• The inner mood is the private sense of harmony that can be

present even if the character is in an environment where events lead to a parallel mood of annoyance.

• The nature of the outer mood is social, and as such tied to emotions that are typically not only directed towards another entity but also often expressed toward an entity, such as anger or amusement.

• The two scales for the mood nodes open up the possibility of more complex states of mind than a single binary axis of moods that cancel each other out.

Mood in Mind Module