developing a believable interactive agent using virtual...

Developing a believable interactive agent using virtual pet design

Tom Battey M.A. Games Design

London College of Communication University of the Arts London

Submission Date: 29/11/2016 Word Count: 5,192

Tom Battey Developing a believable interactive University of the Arts London M.A. Games Design agent using virtual pet design London College of Communication

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Table of Contents

Table of Contents ........................................................................................................................ i

Abstract ...................................................................................................................................... ii

1. Introduction ........................................................................................................................... 1

2. Literature review .................................................................................................................... 1

2a. Social psychology ............................................................................................................. 2

2b. Intelligent agent design ................................................................................................... 3

3. Methodology .......................................................................................................................... 5

4. Design parameters ................................................................................................................. 7

5. Development ........................................................................................................................ 11

6. Conclusion ............................................................................................................................ 16

References ............................................................................................................................... 19

Appendix A: Case Studies ......................................................................................................... 22

Appendix B: Development Diaries ........................................................................................... 26


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Abstract

Interaction with virtual characters is one of the key ways in which games foster emotional

engagement with players. By using the simplified presentation of a virtual pet, this project

aims to identify the way that visual and interaction design can influence emotional

engagement, culminating in the design of a virtual pet software that demonstrates these

principles.

The project will involve reviewing current literature in the fields of social psychology and

intelligent agent design in order to identify useful markers for what makes virtual characters

believable and engaging. These markers will then be applied through a range of case studies

of existing and historical virtual pet software to create a design guideline for a new virtual

pet.

The conclusion of the project will be a virtual pet software developed in Unity (Unity, 2016)

that embodies the core principles of appealing virtual character design and is capable of

creating genuine emotional engagement with its user.


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1. Introduction

Digital agents can have a profound emotional impact on their users. In the case of virtual

pets, research has shown that users form the same kind of emotional bonds with virtual

pets that they might with a real pet, often ‘starting to view them more as companions

rather than just a piece of technology’ (Danauta, 2012, p. 2).

This project aims to identify the foundations of these emotional connections by addressing

the social psychology aspects of interaction design, specifically how interactive technologies

develop emotional connections between users and virtual agents. This research will be

applied through a number of case studies of existing virtual pets in order to define a set of

design parameters that will be used to develop a prototype virtual pet capable of sustaining

emotional engagement with its users.

This report provides the theoretical underpinning and resulting design philosophy of the

project, accompanying the developed software and providing a conclusion to the project

that establishes goals for further development.

Section 2 consists of a literature review of engagement research, with Section 2a dedicated

to social psychology studies and Section 2b focusing on the application of artificial

intelligence technology in virtual pet design. Section 3 provides a methodology outline for

applying this research to the design of a virtual pet, with Section 4 covering the design

parameters devised for this process and Section 5 covering the development process.

Section 6 provides a conclusion, assessing how successfully the developed software met its

design goals and providing a set of practical guidelines for taking this research further.

2. Literature review

Designing for ‘emotional engagement’ requires an understand of both the ‘emotional’ and

the ‘engagement’ parts of that concept. As such, this literature review will be split into two

sections. Section 2a addresses how users invest emotion in games and other interactive

media through the lens of social psychology. Section 2b looks at developments in intelligent


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agent design with regard to virtual pets, addressing how designers and engineers create

compelling user engagement.

2a. Social psychology

In their book Glued to Games: How Games Draw Us in and Hold Us Spellbound (2011), social

psychology researchers Scott Rigby and Richard M. Ryan attempt to unpack the various

elements of game design and define how games engage players from a psychological

perspective. Their Player Experience of Need Satisfaction (PENS) model, which uses self-

determination theory (pp xii) to analyse why people engage with games, defines

‘relatedness’ as one of three core pillars of emotional engagement (pp. 65).

The concept of relatedness in social psychology centres on peoples’ need for interaction

with others. People require acknowledgement from others they meet; they desire support

from others with their specific needs; and they like to feel they have an impact on the other

person (pp. 68). A well-designed interactive character can ‘offer the player the experience of

being relevant to that character’ (pp.69), with a truly interactive character able to ‘provide

thoughtful contingent reactions that successfully yield relatedness satisfactions’ (pp. 71).

This research is supported by the work of Katherine Isbister, whose research focus is social

psychology as it relates to Human-Computer Interaction (HCI). In How Games Move Us

(Isbister, 2006) she defines virtual characters as ‘”living, breathing others” who provide

support, resistance and reactive engagement’ and allow ‘dynamic and reactive engagement’

between a player and the game systems (pp. 20).

In Better Game Characters by Design (Isbister, 2006) Isbister employs a design approach

centred around social psychology to identify the key social equipment a virtual character

requires to be perceived as appealing or engaging. She identifies the face, the body and the

voice as key ‘modes of expression [which] work together to create overall impressions’ (pp.

135). To the extent that these ‘overall impressions’ create an innate sense of appeal in a

character, it is worth looking at historical character design theories to identify the root of

this appeal.


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Ethologist Konrad Lonrenz proposed the ‘Kindenschema’ or ‘Baby Schema’ to define a set of

physical properties present in humans and animals that people find inherently appealing

(Lorenz, 1943). This schema has been researched thoroughly and found to bear good

statistical evidence; see for example the paper by Glocker et al which find that

kindenschema features ‘such as the large head, round face and big eyes’… ‘drive(s) cuteness

perception and motivation for caretaking in adults’ (2009).

The principles of the kindenschema have been used in character design for generations. In

an article for Natural History in 1979, historian and biologist Stephen Jay Gould used Lorenz’

baby schema to explain the evolution of Disney’s Mickey Mouse through the years (Gould

1979). This idea of universally appealing, iconographic character design has developed

further with the Japanese idea of kawaii design, hugely popular in Eastern media and more

recently successful in the West (Winkler, 2013).

Studies into kawaii design and emotional response correlate with the findings of those

looking at the effectiveness of the baby schema; Nittono et al. find that viewing images with

kawaii characteristics gives people an association with ‘cuteness’ and ‘a narrowed

attentional focus induced by the cuteness-triggered positive emotion’ (2012).

This body of research implies that it is possible to define characteristics in a virtual character

that hold universal emotional appeal and increase the chances of fostering emotional

engagement in its audience.

2b. Intelligent agent design

The full scope of work undertaken in the field of intelligent agent design is too broad to be

considered here, so this project will be limited to Joseph Bates’ definition of a ‘believable

agent,’ which is ‘one that provides the illusion of life, and thus permits the audience’s

suspension of disbelief’ (Bates, 1994).

Breaking down the idea of ‘believability’ further, Mateas and Stern focused on the concept

of ‘agency’, posited by Janet Murray in Hamlet on the Holodeck (Murray, 2000), when

building interactive drama Façade (Mateas & Stern, 2005). ‘Agency’ as defined here means


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‘the player has actual, perceptible effects on the virtual world’ (2005). In designing the

virtual characters for Façade, Mateas and Stern outline a series of design principles for

virtual agents that remain to this day a useful template for those wishing to design suitably

believable virtual agents.

Many of these points mirror those in Bates’ work; for example, the use of ‘procedural and

keyframe animation’, ‘low-level reactive behaviours’ and ‘long-term autonomous

behaviours’ (Mateas & Stern, 2005) show an applied interactive version of Bates’ reference

to classic animation principles (Bates, 1994) first proposed by ex-Disney animators Frank

Thomas and Ollie Johnston (Thomas and Johnston, 1981).

Mateas’ more recent work alongside Ryan, Summerville and Wardrip-Fruin addresses the

need for believable agents to express more complex emotional behaviour. Their paper

Towards Characters Who Observe, Tell, Misremember and Lie identifies the problem of

‘unbelievable character behaviors such as perfect recall or the awkward divulging of

information in a way that is obviously harmful to the teller’ (Ryan et al., 2015). Their

proposed solution employs a series of mental models controlled by an A.I. behaviour with

the intent of creating believably unpredictable character responses. They also provide a

comprehensive review of work undertaken both commercially and academically that shaped

their approach to developing believable agents.

Considering virtual pets specifically, Catrinel Danauta provides an overview of some of the

social and technical challenges in designing a virtual pet as opposed to a human-like agent,

observing the systems employed by Sony AIBO and Pleo to give them the illusion of life and

foster engagement with their audience (Danauta 2012).

Goertzel et al. propose a way to address these challenges using a combination of ‘fast

learning’ and ‘deep learning’ processes to develop virtual pets capable of learning

behaviours via simulation of real-life dog training techniques (2008). These algorithms,

however, take time to train and presuppose a user acting in a ‘trainer’ role, so may not be

suitable for real-time behaviour development. Herrera, Victoria and Quinones propose

using ‘reinforcement learning’ to develop a virtual pet that can learn behaviours from


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repeated interactions with its environment, simulating how animals learn in nature (Herrera

et al., 2012).

These approaches are similar in some ways to those of Ryan at al. (2015), especially in the

way the A.I. seeks to resolve the changing relationship between an agent and its

environment, but these present an ‘animal like’ learning approach more specific to the

design of a virtual pet than the ‘human like’ approach used in, for example, the

development of Façade.

3. Methodology

The design process behind the prototype virtual pet produced during this project was

informed by research into both the history and present state of the virtual pet in the

marketplace. This research involved a series of case studies spanning the history of the

virtual pet, with the purpose of developing a broad understanding of how virtual pets

engage their users, and applying this understanding to produce a series of design

parameters to govern the development of the software.

These case studies took the form of textual analyses of interactive systems, as proposed by

Daine Carr (2009). Carr built on work by Barthes (1974, 1977a, 1997b) to suggest that

analysis of an interactive text such as a videogame requires a textual analysis, concerned

with the meaning of the complete text isolated from the process of its construction; a

structural analysis, concerned with the rules and systems underpinning the text, and an

inter-textual analysis, concerned more with the relationship between the text and its

audience, and with wider society.

The case studies for this project were analysed under three headings which aim to satisfy

this definition of a textual analysis. The illusion of life, a reference to Bates’ citing of classic

Disney animators (Bates, 1994 pp.01), is concerned with how effectively a virtual pet

promotes the idea that it is a living creature, considering technical, mechanical and

aesthetic elements as a single complete entity.


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Interaction design considers the design of the technology and systems used to create the

virtual pet. Here, analysis is concerned with the practicality of how a user interacts with the

virtual pet, and how the system delivers the experience of a believable pet back to the user.

Social factors consider the virtual pet as part of wider society, placing it historically as part

of a broad marketplace. Analysis of social factors aims to take into account how outside

factors may have had an impact on the success and overall effectiveness of the virtual pet in

question.

The case studies undertaken were: Petz (1995), Tamagotchi (1996), Creatures (1996), Furby

(1998), Neopets (1999), PARO (2003), Pleo (2007), My Boo (2013), Neko Atsume (2014) and

Daily Kitten (2014). This selection was chosen to provide a broad range of designs and form

factors across the history of the virtual pet. A breakdown of all case studies and links to the

full studies can be found in Appendix A.

Where possible the case studies were conducted with first-hand experience; for older or

unavailable products data was gathered from historical reports and product reviews

archived online in order to create an impression as close as possible to that available at the

time of product launch.

The purpose of these case studies was to generate data to define a set of design

parameters, or ‘virtual pet best practises’, which defined the design stage of the project.

The project design parameters are covered in more detail in Section 4. Design of the

software itself followed the MDA framework, which considers the role of mechanics (the

rules and systems underpinning the software), dynamics (how a user is able to interact with

these rules and systems) and aesthetics (a user’s subjective experience of these

interactions) both from the point of view of a developer, building from the ground up, and

that of a user, approaching the software as a complete isolated experience (Hunicke,

LeBlanc and Zubek, 2004). More on the software development process can be found in

Section 5.


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4. Design parameters

Design persistent systems.

Persistence is a core element of what makes a virtual pet engaging; persistent systems are

present in all of the evaluated case studies. On the simplest level, persistence means a

virtual pet ‘remembers’ its needs and vocalises them in some way to the user, like a

Tamagotchi’s demanding beeps when it’s hungry. On an advanced level, persistence can be

seen in behaviour patterns that change and develop consistently over time, and can even be

passed down to digital ‘offspring’.

Designing persistent systems means designing systems that work in real time, and do not

require a player’s attention or input to run. In the prototype developed here, this is done

through a timer system that is capable of keeping track of time even when the software is

‘switched off.’ This persistent timer is then used to update the virtual pet’s needs – its

hunger, sleepiness, boredom, etc. – its overall mood, which is tied to these needs, and the

state of objects in the world around it. For example, the amount of food remaining in the

pet’s food bowl is calculated based on its hunger levels over time, and adjusted accordingly

until no food is left and the user needs to refill the bowl.

These persistent systems exist to give the impression that the virtual pet is living its own life,

in real time, independently of the user’s actions.

Form factor should be optimised for portability.

Concurrent with the idea of persistence is the requirement that a virtual pet be as portable

as possible. This allows users to ‘take their pet with them’ wherever they go, and gives them

the opportunity to ‘check in’ with the pet much more often, reinforcing the desired

relationship between pet and user.

A portable form factor was part of what made the original Tamagotchi so widely engaging,

and is likely also the reason that the most popular virtual pet software released in the last

five years has been on mobile platforms. Developing for mobile devices like phones and


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tablets allows designers to integrate a virtual pet into a user’s everyday routine, increasing

the likelihood of them interacting with the pet on a regular basis.

For this reason, the project prototype will be developed for iOS devices, primarily iPhone

and iPad. Limiting development to iOS platforms allows the design to be optimised for

mobile without having to account for the wide range of different device specifications

provided by Android and Windows handsets, whilst still providing the opportunity to port to

these devices at a later stage of development.

The concept of portability extends beyond the hardware the virtual pet runs on; the

software itself should be portable, able to be accessed, interacted with, and closed again as

quickly as possible. From a development perspective, this means keeping the overall app

size small and the loading times as short as possible. From a design perspective, it means

ensuring the app loads directly into the interactive scene without the need for menu

interfaces or other clutter.

Natural input, minimal interface.

Interacting with the virtual pet should feel as natural as possible, with the goal being the

feeling that the user is reaching out and touching their pet through the screen of the device.

Touchscreen technology helps with this, allow simple, naturalistic gestures such as rubbing

directly on the pet to ‘stroke’ them or ‘flicking’ a ball to send it flying across the screen.

It’s also important to follow the standard lexica of touchscreen controls – universally

understood gestures such as ‘pinch to zoom’ and ‘swipe’ navigation which have developed

over the lifetime of touchscreen devices. The more the software behaves as the user

naturally expects it to, the more they are able to forget about the software and focus on the

actual pet itself.

This philosophy of the software ‘getting out of the way’ of the relationship between the pet

and the user extends to the design of the interface itself. Wherever possible, all information

and interaction should be communicated through the ‘physical’ elements of the game

world, be it the pet itself or the objects around it. All visual elements that do not directly


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relate to the user interacting with the pet – such as menus, statistics, buttons and metres –

should be minimised or removed entirely.

Communicate data visually.

In order to achieve the desired minimisation of unnecessary visual content, the visual design

of the pet itself has to communicate as much information as possible. A combination of

iconographic illustration, animation techniques and interactive drama are used to design a

virtual pet that is as visually expressive as possible.

Using the established kawaii visual style (Winkler, 2013) enables the creation of expressive,

readable faces capable of expressing a full range of emotions without requiring a level of

visual complexity that will affect performance.

The animation of the virtual pet will be based on long-proven principles of animation,

proposed by ex-Disney animators Frank Thomas and Ollie Johnston (1981). To summarise

briefly, these consist of: timing and spacing; squash and stretch; anticipation; ease in and

ease out; follow through and overlapping action; arcs; exaggeration; solid drawing; appeal;

straight ahead and pose-to-pose; secondary action and staging.

By combining expressive kawaii facial design with these animation principles, the virtual pet

designed for this project is capable of expressing a range of needs and behaviours through

visuals alone, removing the requirement for ‘need bars’ and other visual information that

distracts users from interacting with the pet.

Every action has a reaction.

To reinforce the illusion that the virtual pet is a real creature with awareness of the world

around it, it should react to every action the user takes. This means that a reaction has to be

designed for every action it’s possible for a player to take; care was taken to create a

response for every time the user touches the screen.


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A simple example of this is that if the user taps on an empty part of the screen the pet will

turn and look at them, as if it ‘lives’ on the other side of the glass screen and can ‘hear’ the

user tapping on it. Small reactions like this reinforce the pet’s illusion of life.

Predictable and unpredictable responses.

Designing for believability requires the virtual pet to react as much like a real animal as

possible. For this reason, the pet’s behaviour needs to be predictable enough to not seem

completely random, but unpredictable enough to be believable as an independent thinking

agent. As a real life example, a cat will behave mostly predictably when it’s hungry –

meowing, running to its food bowl, etc. – but it won’t meow at the exact same time or run

the exact same route to the bowl.

Designing A.I. to react like this is a challenge – A.I. programs tend to be good at being

completely random or completely predictable, but less so at portraying a convincing level of

unpredictability. The solution used for this project employs series of personality ‘curves’

which track the pet’s internal state over time and adjust its behaviours according to both its

inbuilt tendencies and input from the user.


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5. Development

The virtual pet developed to meet these designed parameters is Catbox (Figure 1), an app

for iOS devices featuring a cube-shaped cat capable of exhibiting distinct personalities that

change over time.

Figure 1: Development of the Catbox visual design, from initial sketch to 3D model.

Visual.

The visual design of Catbox is based heavily on the parameters of kawaii drawing, with a

simplified facial design capable of expressing a wide range of emotions clearly and

remaining readable at a distance. The simple cube body shape allows the character to be

animated quickly and easily, and displayed on mobile devices with clarity and minimal

computational overhead. The more fluid tail contrasts with the rigid body, allowing for a

greater range of motions and expressions that are familiarly ‘cat-like.’

Catbox is developed in Unity (Unity, 2016). 3D assets are created and animated in Maya

(Maya, 2016), and textures and 2D assets are created in Illustrator (Adobe Illustrator CS6,

2012). Animations for the Catbox character are created using a mixture of blend shapes and

inverse kinematics. Blend shapes are applied to the body of the character (Figure 2) to allow

fluid squash, stretch, twist and tilt animations to be applied to the otherwise rigid cube

shape. The tail is animated using a joint chain constrained by an inverse kinematic spline

curve (Figure 3), enabling a wide range of flexible motion. An animation control rig was

developed for Catbox to allow quick and easy manipulation of these different parameters.


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Keyframed animations are imported from Maya into Unity as Animation Clips, which are

then attached to the in-game Catbox object. The Catbox in the current prototype build has

25 different Animation Clips that make up its visual range of behaviours. Textures for the

character are drawn in Illustrator and applied to the model with a UV map.

Figure 2: The range of blend shapes that are

used to control the shape of Catbox’s body.

Figure 3: The IK chain and spline controller used

to manipulate Catbox’s tail.


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Catbox uses multi-layered textures to allow the

character to be displayed in a potentially unlimited

range of colours whilst maintaining full controls over

facial expressions. The first layer is the base body

colour; the second is the secondary colour; the third

layer is the facial detail, and the fourth is used to show

dirt (Figure 3). The colour layers are set at

initialisation, while the face layer is controlled by the

Animator to provide a range of different facial

expressions. While the prototype Catbox only has a

solid body colour, this multi-layered approach to

texturing allows for the easy implementation of

different patterns and coat styles in future updates.

Structural.

The Catbox game system is controlled by a series of

cross-referenced C# scripts, applied in a modular

fashion. This approach allows different behaviours to

be developed independently of the rest of the game’s

code, then integrated with existing scripts as required.

This makes it relatively simple to keep track of which

scripts are currently acting on Catbox, and allows new

behaviours to be developed and integrated quickly

without the risk of compromising existing code, making an iterative development approach

easier in the future.

The game’s scripts are divided into four categories; system, controller, behaviour and input

scripts. System scripts deal with high-level software functions such as monitoring the

passage of time and saving and loading data. Input scripts monitor the user’s physical

interactions with the device, such as taps, swipes and pinches. Controller scripts apply to

Catbox directly and monitor its various variables, activating and deactivating behaviour

scripts as required. The behaviour scripts control what Catbox actually does in the scene,

Figure 4: Example of the multi-layered

texturing used on the Catbox model.


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the actions and reactions depending on inputs from other scripts. Figure 5 provides a visual

representation of how these scripts interact.

Intelligence.

Developing A.I. capable of providing the required range of ‘predictable and unpredictable

responses’ whilst remaining simple enough to deploy on mobile devices proved to be the

primary design challenge of the project. Early attempts were made using an experimental

application of a supervised learning method called support vector machines (Steinwart and

Christmann, 2008) where game A.I. is trained using a dataset based on the various needs of

the virtual pet – unhappiness, hunger, tiredness, bladder, dirtiness and sickness – to choose

an appropriate action from a range of pre-defined behaviours. The system is trained with a

Figure 5: A visual representation of how the game systems modular scripts act on Catbox.


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Unity plugin called CoAdjoint Orbit (Matcham, 2014), which exports a .dll file that can then

be imported into project and accessed to select behavioural responses.

This system was moderately successful, in that it did select behaviours approximate to those

predicted based on the pet’s various needs, but had a number of drawbacks. The

requirement of a large number of manual data inputs, the inflexibility of the trained A.I. and

incompatibility with mobile platforms led to the machine learning approach being

abandoned despite some initially promising results.

The A.I. that controls Catbox in the prototype is instead based on a series of curves which

dictate how the pet’s needs change over time as well as how it responds to its various

needs. ‘Nature’ curves dictate the simple increase of these needs over time, as defined by

the pet’s pre-determined personality type, while ‘age’ curves control how this nature

changes as the pet ages. ‘Threshold’ curves dictate at what point a certain need will begin to

affect the pet’s overall happiness, and these also change as the pet ages. ‘Nurture’ curves

are effected by interactions from the user, allowing the pet’s personality to change

according to a user’s actions over time.

This system roughly emulates the ‘nature and nurture’ paradigm believed to influence real

animal behaviour (Breed & Sanchez, 2010). At any point, the system can check the time

passed against the age of the pet, and retrieve an average of the four curves to make a

decision about how the pet should respond to a given need. Potential responses are added

to or removed from a list class as the curve value requires, with the pet’s actual response

being selected at random from this pool.

This system proves flexible and dynamic, with responses being random enough to seem

believably unpredictable whilst the curves ensure the range of possible responses remains

true to the pet’s age, personality type and the current state of its needs.

At initialisation the pet is assigned a particular personality type which dictates the shape of

its behaviour curves. A ‘greedy’ type pet might have a steeper ‘hunger’ curve, for example.

These behaviours can then be reinforced or altered depending on the user’s actions;

frequently feeding a pet treats will increase its demand for food, while brushing it regularly

encourages it to keep itself clean.


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Interaction.

In keeping with the requirement for natural interactions and mobile focus, the Catbox app is

controlled entirely with the touchscreen on a mobile or tablet device. The prototype is

compatible with iPhone and iPad platforms, with content scaling dynamically to fit the

specification of the device it is running on.

Interactions with the game follow the best practices of natural touchscreen design, outlined

briefly by the Embedded Interaction Lab (no date). Users interact with on-screen objects,

including the pet itself, by tapping on them to engage. Items in the game can be dragged

around with a finger on the screen, and those with a physical presence in the space can be

tossed and flicked around with touch gestures. These inputs are designed to imitate those

used in most common touchscreen-based software to minimise interface interference.

The game also features interactions less common in typical touchscreen software, but which

are used to enforce the idea that Catbox is a living creature. When interacting with the pet,

players can rub their finger directly over the character to ‘pet’ it. Brushing the pet involves

dragging a brush over its body, while feeding it treats involves physically dragging a treat to

its mouth.

All of these actions are designed to feel as natural as possible by simulating real-life

interactions with a pet, and Catbox will immediately respond with sound and animation to

positively reinforce the action. These interactions are designed to promote Catbox’s illusion

of life and encourage users to engage with the virtual pet in a close approximation to how

they might with a real pet. A breakdown of the full development process and links to

development diaries can be found in Appendix B.

6. Conclusion

The objective of the Catbox project was to design a virtual pet that meets the design

parameters outlined in Section 4 of this report, which were written as a response to a


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literature review of texts focusing on virtual pet design and a series of case studies which

examined the design and development of virtual pets from 1995 to 2016.

The result of this development is Catbox, a virtual pet game for iOS devices, which features

a virtual pet capable of displaying distinct personalities that change over time, both

according to the pet’s designed nature and its interactions with the user. The conclusion to

this report will examine how the prototype meets the design parameters of the project, and

will briefly touch on how the project could be expanded and developed in future.

Catbox is controlled by persistent systems, which track the state of the pet through time

even when the user is not actively engaged with the game. Catbox is capable of acting

independently while the game is switched off, and will take care of its own needs provided

it is kept supplied with the required resources by the user. Catbox ages over time, with its

age changing its personality and requirements.

The game is optimised for portability, using low-polygon models and mobile-optimised

textures. The demo build has been tested to run on iOS platforms, from iPhone 5C (and

upwards) and iPad Mini 2 (and upwards). The game’s UI and visual scale automatically to

the screen size of the device they run on, providing the potential to run on a range of other

mobile devices in future iterations.

Interactivity is based on natural input with minimal interface. Wherever possible, users

interact with their pet using established natural touchscreen input. Most input is achieved

by direct interaction with objects in the game world. Where UI features are necessary they

are integrated into the game world and follow same rules of natural input as the rest of the

game. The user’s every action has a reaction; the pet will respond to the user’s every input,

down to indicating surprise when the user ‘taps’ the glass of the touchscreen.

The design of the Catbox character allows it to communicate data visually. Clear and

readable facial expressions allow users to easily identify the mood of their pet, while

exaggerated animations let the pet perform a range of actions and expressions. The

expressive nature of Catbox removes a reliance on UI elements – users are able to identify

the state of their pet from its actions and expressions.


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Catbox’s A.I. allows it to perform both predictable and unpredictable responses. Need

curves control its range of potential actions over time, ensuring it acts in accordance with its

inner emotional state, but randomisation of the list class means that the system can never

guarantee exactly which action will be performed next.

By fulfilling these design parameters, the Catbox software meets the needs of the brief

established in Sections 2 and 4, and more broadly achieves the goal of drawing on virtual

pet design to develop a believable interactive agent. Which is not to say that the project

could not be expanded and improved upon.

Future development of the project would first involve rigorous user testing, gathering

qualitative data on user responses to Catbox. Users would be asked to ‘care’ for Catbox over

a set period of time, with data collected via interview and surveys at various points in the

process in order to establish the developing relationship between the user and their virtual

pet.

This data would lead to an iterative development cycle aimed at improving the software

according to audience response. This approach would improve Catbox according to actual

established user engagement over several iterations, leading to piece of software better

capable of achieving lasting emotional engagement and better meeting the requirements of

this project.


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References

Literature Barthes, R. (1974). S/Z (R. Miller, Trans.). Oxford: Blackwell. Barthes, R (1977a) ‘Introduction to the Structural Analysis of Narrative’ in Image Music Text (S. Heath, Trans.). London: Fontana Press pp 79-124 Barthes, R (1977b) ‘The Struggle with the Angel; Textual analysis of Genesis 32: 22-32’ in Image Music Text (S. Heath, Trans.). London: Fontana Press. pp 125-141 Bates, J. (1994). The role of emotion in believable agents. Communications of the ACM, 37(7), pp.122-125. Blumberg, B. (2001) ‘Learning in Character: Building Autonomous Animated Characters That Learn What They Ought to Learn’, in Balet, O; Subsol, G and Patrice Torguet (eds.) ICVS '01 Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. London: Springer-Verlag, pp 113-126. Breed, M D. & Sanches, L. (2010) Both Environment and Genetic Makeup Influence Behavior. [online] The Nature Education Knowledge Project, powered by Scitable. Available at: http://www.nature.com/scitable/knowledge/library/both-environment-and-genetic-makeup-influence-behavior-13907840 (Accessed 08 Nov. 2016). Carr, D. (2009) Textual Analysis, Digital Games, Zombies. [online] London Knowledge Lab, Institute of Education University of London. Available at: http://homes.lmc.gatech.edu/~cpearce3/DiGRA09/Tuesday%201%20September/306%20Textual%20Analysis,%20Games,%20Zombies.pdf (Accessed 10 Oct. 2016). Embedded Interaction Lab (no date). Touch Screen Gestures [online]. Available at: http://www.embeddedinteractions.com/touch%20screen%20gestures.html [Accessed 09 Nov. 2016]. Danauta, C.M. (2012) Virtual pets: interaction, uses, technology. [online] School of Electronics and Computer Science. University of Southampton. Available at: http://mms.ecs.soton.ac.uk/2012/papers/21.pdf (Accessed: 12/09/2016). Glocker, M. L., Langleben, D. D., Ruparel, K., Loughead, J. W., Gur, R. C., & Sachser, N. (2009). Baby Schema in Infant Faces Induces Cuteness Perception and Motivation for Caretaking in Adults. Ethology : Formerly Zeitschrift Fur Tierpsychologie, 115(3), 257–263. http://doi.org/10.1111/j.1439-0310.2008.01603.x Goertzel, B et al. (2008) ‘An Integrative Methodology for Teaching Embodied Non-Linguistic Agents, Applied to Virtual Animals in Second Life’, in Wang, P., Goertzel, B. and Franklin, S. (2008). Artificial general intelligence, 2008. Amsterdam: IOS Press.

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http://www.nature.com/scitable/knowledge/library/both-environment-and-genetic-makeup-influence-behavior-13907840

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Gould S.J. (1979) Mickey Mouse meets Konrad Lorenz. Nat Hist.88:30–36. Herrera, R. R., Victoria, L. and Quinones, R. (2012) Reinforcement learning model for virtual pets. International Journal of Advanced Research in Computer and Communication Engineering, 1,(9), November 2012 . Hunicke, R., LeBlanc, M. and Zubek, R. (2004) MDA: A formal approach to game design and game research. Proceedings of the AAAI-04 Workshop on Challenges in Game AI (25--29 July 2004), pp. 1-5 Isbister, K. (2006). Better game characters by design. Amsterdam: Elsevier/Morgan Kaufmann. Isbister, K. (2016). How games move us. Cambridge, Massachusetts: The MIT Press. Lorenz, K. (1943). Die angeborenen Formen möglicher Erfahrung. Zeitschrift für Tierpsychologie, 5: 235–409 Nittono, H., Fukushima, M., Yano, A. and Moriya, H. (2012). The Power of Kawaii: Viewing Cute Images Promotes a Careful Behavior and Narrows Attentional Focus. PLoS ONE, 7(9), p.e46362. Mateas, M. and Stern, A. (2005) Build It to Understand It: Ludology Meets Narratology in Game Design Space. DiGRA '05 - Proceedings of the 2005 DiGRA International Conference: Changing Views: Worlds in Play 3. Murray, J.H. Hamlet on the holodeck: the future narrative in cyberspace. (2000). United States: M I T Press (MA). Rigby, S., & Ryan, R. M. (2011). Glued to games: how video games draw us in and hold us spellbound. Santa Barbara, Calif: ABC-CLIO Ryan, J.O., Summerville, A., Mateas, M. and Wardrip-Fruin, N. (2015). Toward characters who observe, tell, misremember, and lie. Proc. Experimental AI in Games, 2. Steinwart, I. and Christmann, A. (2008). Support vector machines. New York: Springer. Thomas, F. and Johnston, O. (1981). Disney animation. New York: Abbeville Press. Winkler, M. (2013). What Exactly is this Japanese Trend Known as Kawaii [online] Design & Illustration Envato Tuts+. Available at: https://design.tutsplus.com/articles/what-exactly-is-this-japanese-trend-known-as-kawaii-all-about--vector-15984 (Accessed 19 Sep. 2016). Software. Adobe Illustrator CS6. (2012). San Jose, CA: Adobe Systems Incorporated.


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Appendix A: Case Studies

The following is a summarized list of the case studies undertaken for this project, the web addresses of the full text of each.

Case Study: Tamagotchi

Tamagotchi, originally a hand-held device containing a virtual chicken, is widely considered the first true virtual pet. Released in Japan in November 1996, and the U.S. in May 1997, the toy’s release sparked a craze of popularity that has seen it sell over 76 million copies as of 2010, with various iterations of the toy appearing through the years.

This case study will mostly concern the original 1990s Tamagotchi as the progenitor of the virtual pet. Most of my research comes from this study of Tamagotchi from 2001, conducted by Jef Samp at UC Berkeley.

Web address: http://tombattey.com/design/case-study-tamagotchi/

Case Study: Furby

Furby, first released in 1998, is a physical soft toy with mechanical parts and a computerised brain. Its physicality, and the fact that it can respond to physical touch, differentiated Furby from other virtual pets available at the time such as Tamagotchi and Digimon, and made it the best selling toy at Christmas for three years running.

Produced by Tiger Electronics and designed by inventor David Hampton, who had previously worked at toy company Mattel as well as on classic videogame Q-Bert, the Furby was an attempt to make a Tamagotchi-style virtual pet that felt and reacted like a real, living animal. With sales exceeding 27 million in one 12-month period, and a 1999 sales forecast of $300 million from parent company Hasbro, the toys were hugely successful.

The original Furby model was discontinued in 2002, to be revived in 2005 and again in 2012, with later generations of Furby adding new features and functions. This case study will largely be concerned with a historical analysis of the original 1998-2002 Furbies, with a brief follow up describing changes made to the toy to bring the design up to date.

Web address: http://tombattey.com/design/case-study-furby/

Case Study: Petz

Petz originated as a desktop virtual pet for the Windows PC. Designed by Night Trap designer Rob Fulop, the first title in the series, Dogz, was released in 1995. Originally published by PF. Magic and billed as ‘the original virtual pet,’ Petz was largely overshadowed by the release of the Tamagotchi the following year, and was later acquired by Ubisoft and reintroduced in a form that resembles little of the 1995 original. Even so, the game had a strong following at the time and is fondly remembered by enthusiasts today.

http://tombattey.com/design/case-study-tamagotchi/

http://tombattey.com/design/case-study-furby/


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This case study concerns the original Dogz and Catz games, rather than the modern Ubisoft-published titles.

Web address: http://tombattey.com/design/case-study-petz/

Case Study: Creatures

Creatures is a life simulation software designed by computer scientist Steve Grand, and first released as a commercial game for Windows in 1996. Originally conceived as a virtual pet that could live on your desktop and interact with other Windows software, this ‘virtual mouse’ idea eventually became a broader experiment in artificial life, featuring semi-intelligent creatures called ‘norns’ which inhabit the planet Albia.

Players were tasked with nurturing a population of norns through multiples generations, assisting them in navigating their environment and avoiding the unwanted attention of the sinister grendel. Creatures released as three central games (Creatures, 1996, Creatures 2, 1998, and Creatures 3, 1999) with an online expansion Docking Station released in 2001. Several spin-off games were also released, including titles aimed at younger children and a release for the original Playstation console. This case study is primarily focused on three releases in the main series.

Web address: http://tombattey.com/design/case-study-creatures/

Case Study: Neopets

Neopets is an online community website and micro-game platform that centres around the raising and customising of virtual pets. Players can own a number of pets from 54 possible species, take care of them by feeding them special items, and customise them by changing their colour or giving them special equipment. Pets are seen as status symbols by users, who take part in a lively community, with rare breeds, colours and equipment being highly desirable.

Neopets was originally conceived by British student Adam Powell and partner Donna Williams in 1999, with the site being incorporated as Neopets, Inc. by American businessmen Doug Dohring in 2000 following the initial success of the site. Neopets has since been owned by Viacom (2005 – 2014) and JumpStart (2014 – present). The nature of the site changed dramatically under its various ownerships, prioritising advertising and commercial content in its later iterations.

Web address: http://tombattey.com/design/case-study-neopets/

Case Study: PARO

PARO, a physical form factor robot pet developed by AIST and first released in 2003, is an

attempt to use appealing virtual pet design in the mould of Furby to improve quality of life.

PARO is primarily focused on helping elderly people less able to care for real pets,

http://tombattey.com/design/case-study-petz/

http://tombattey.com/design/case-study-creatures/

http://tombattey.com/design/case-study-neopets/


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particularly those suffering with dementia and confined to care homes, where access

to flesh-and-blood therapy animals can be difficult.

The therapeutic benefits of engagement with animals have been well documented, and

PARO is just one example of designers using robots to emulate this beneficial

companionship in a way that is more accessible to those who may find it difficult to care for

a real animal. There are many of these therapy robots in existence; this case study will use

PARO to examine how engaging pet design can emulate the therapeutic benefits of a

relationship with a real animal.

Web address: http://tombattey.com/design/case-study-paro/

Case Study: Pleo

Pleo is a robotic dinosaur ‘life form’ manufactured by Innvo Labs, first revealed in 2006 and released at retail at the end of 2007. Using a similar combination of robotics and artificial intelligence to PARO, Pleo is capable of responding to human contact and developing distinct personalities depending on its interactions with its user.

Where PARO is targeted specifically at care services, designed to aid elderly patients suffering with loneliness or the onset of dementia, Pleo uses similar technology to develop a robotic pet aimed at a commercial market.

Web address: http://tombattey.com/design/case-study-pleo/

Case Study: Neko Atsume

Neko Atsume: Kitty Collector is a mobile game available on iOS and Android platforms which centres around building a virtual garden to attract a host of colourful cats to visit. Players purchase different types of food and furniture with either currency earned in game or purchased with real-life money; these can then be dropped into your garden, and different cats will appear over time depending on which items are available to them.

Neko Atsume was designed by Yutaka Takazaki of Hit-Point, and released in Japan in October 2014. The game was later translated into English by studio 8-4, and released on Western app stores in October 2015. The game proved incredibly successful, passing 5.5 million download as of July 2015, with current downloads estimated to be close to 10 million.

Web address: http://tombattey.com/design/case-study-neko-atsume/

Case Study: Daily Kitten

Daily Kitten is a virtual pet game for iOS and Android devices developed by Honikou Games. The game centres around taking care of a 3D animated kitten, ensuring it’s well-fed, clean and rested, and playing mini-games to score point which can be spent on items in game. The

http://tombattey.com/design/case-study-paro/

http://tombattey.com/design/case-study-pleo/

http://tombattey.com/design/case-study-neko-atsume/


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game is free to play, but new toys and items for the kitten can be purchased with real money via in-app purchases.

From the game’s Google Play page: ‘Daily Kitten offers you your own cat; it’s just for you. It can do anything as long you take care of it. Caress it, feed it, teach it to stay clean, play with it, put it to sleep … you can accompany it in its dreams, dress it up the way you like and make it purr when you stroke it. To make a long story short, it’s your new companion and you help it grow and have a lot of fun.’

Web address: http://tombattey.com/design/case-study-daily-kitten/

Case Study: My Boo

My Boo is a virtual pet and mini game compilation game developed by Tapps Games and available on iOS, Android and Amazon devices. Players take care of a cheerful-looking blob creature called Boo, which can be customised with a wide range of colours and features earned with in-game currency generated by playing mini games.

Mini games are unlocked as Boo levels up through continuous interaction. The game is free to play and ad-supported, with options for players to pay to remove ads and win more in-game currency. There is an emphasis on player-to-player interaction, with players able to share their Boo’s design through both traditional social media and dedicated My Boo sharing platforms provided by Tapps Games.

Web address: http://tombattey.com/design/case-study-my-boo/

http://tombattey.com/design/case-study-daily-kitten/

http://tombattey.com/design/case-study-my-boo/


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Appendix B: Development Diaries

The following list of development diaries were produced during the development of Catbox, and are included here with web addresses to provide a more complete overview of the software development process.

Visual design of a virtual pet

A detailed look at the development of the Catbox visual design. Web address: http://tombattey.com/design/visual-design-of-a-virtual-pet/

Catbox Visual Development

An overview of how the visual design was implemented in Maya and Unity. Web address: http://tombattey.com/design/catbox-development/

Catbox Animation Test

An interactive animation test showing early animation development and implementation in Unity. Web address: http://tombattey.com/design/catbox-animation-test/

Catbox Behaviour Design

A detailed look at the development and implementation of the behavior systems that control Catbox. Web address: http://tombattey.com/design/catbox-behaviour-design/

Catbox Interface Design

An overview of the development and implementation of the UI elements that are used to interact with Catbox. Web address: http://tombattey.com/design/catbox-interface-design/

Catbox Future Development

A summary of the submitted Catbox prototype and some ideas for testing and developing the application further in the future. Web address: http://tombattey.com/design/catbox-future-development/

http://tombattey.com/design/visual-design-of-a-virtual-pet/

http://tombattey.com/design/catbox-development/

http://tombattey.com/design/catbox-animation-test/

http://tombattey.com/design/catbox-behaviour-design/

http://tombattey.com/design/catbox-interface-design/

http://tombattey.com/design/catbox-future-development/

developing a believable interactive agent using virtual...

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