Master’s Thesis: Evaluating the Advantages of Physical and Digital Elements in Hybrid Tabletop Games

Preface

A few weeks ago, I finished my studies at the HTW Berlin in International Media and Computing with the defense following my master’s thesis. I thought that its content might be interesting to others on the internet too, but I understand that not everyone wants to read 100+ pages. For that reason, I am now writing this “too long; didn’t read” summary. It is also a lot more informally written. If you like what you read, you are quite welcome to read the longer version too! Here are the links:

Master’s Thesis

Source Code (open source, MIT license), Screenshots, Photos, Videos etc.

You can also read this summary as a PDF, but you would miss out on the videos.

Introduction

I love board games just as much as I love digital games. With smartphones and tablets, digital board games are getting bigger and bigger. But those are mostly touch-based – and at the HTW I had the chance to make games with a MultiTaction Cell multitouch table which can recognize objects placed on top of it too. So now, in my thesis, I wanted to find out if I can create digital-physical tabletop hybrid games that provide better gameplay than a touch-only version could.

I didn’t want to do something like chess which could be played with physical tokens, as a touch-based digital game or as a hybrid game without changing gameplay at all. I set out to focus on game prototypes where neither the digital and physical elements could be removed without changing the gameplay – a “true hybrid”, only possible in combination. Core physical elements should be interactions with advantages in the physical world, for example using the sense of touch to quickly and intuitively manipulate objects without directly looking at them, real-world physical interactions between pieces or using other properties of physical artifacts – e.g. objects can look different depending on the viewing angle. Likewise, the digital aspect is not just used for the sake of technology, but to add gameplay elements that are only possible by using technology.

I quickly figured out that it is easy to make the digital side matter, but almost everything physical that the multi-touch table can still recognize can also be closely simulated digitally. This shifted the focus a bit: Instead of still trying to make “true hybrids”, I wanted to make tabletop game prototypes that I believe are improved by the physical/digital combination. Every prototype would get a hybrid and a touch-based-only version, and then I can compare those in user tests.

Physical/Digital Advantages

Before I started with the design of the prototypes, I analyzed board games and digital games to find out which advantages they have over the other side. Note that a lot of those have exceptions, e.g. digital games are more likely to have a tutorial, but there are also board games with tutorials – and flicking might have advantages in the physical world, but digital games have similar mechanics. Mechanics and properties that are listed here are not exclusive to either side; I just believe that one side does it easier or might do it better in some way.

My thesis also has a short chapter on pervasive games, but since the focus is on making a tabletop hybrid game, I’ll leave this out here.

Physical Advantages – with a focus on board games

Physical Interaction

The physical world provides tactile feedback and often allows for more fine-grained movement.

Finger Flicking: Done in games like Carrom and Crokinole, sometimes also thematic games like the dungeon-crawler Catacombs. Can be simulated with quick swish-motions on touch screens or pull-back mechanics in the digital world.
Gravity: Games like Bausack or Jenga are built around building, balancing or removing building blocks in 3d space. It is hard to simulate the small movements and the tactile feedback in a digital game, although many 2d physics games exist.
Tools: Games like Operation or Gone Fishin’ are based around tools used to interact with the game to give it a certain feeling or mechanics. These are much easier and often cheaper to produce for a physical game; the digital equivalent would be custom controllers.

Hidden State in a Shared Space

Tabletop games use independently movable physical parts which allows players to look at information (for example the underside of a card or token) without the other player seeing the same information. This is not possible on a single shared digital screen on multi-touch table or tablet. Digitally, this can be solved by using multiple screens or having a player look away, so either the space is not shared anymore or the flow is often broken.

Player Interaction

Interacting and communicating with other people is much easier when the partner is in the same room, instead of through text and speech or even through a webcam.

Communication and Party Games: Games like Taboo, Pictionary, Charades and Freeze are heavily reliant on communication – be it speaking, drawing, gesturing or full-blown acting. Speaking and drawing can be replicated in digital games as well and might just be more enjoyable in a setting with everybody in the same room; when more body language and atmosphere is involved though, making a good digital equivalent harder or even impossible to create.
Reading People’s Faces: Games like Junta or those in the Werewolf/Mafia family are heavily based on observation, negotiation and/or calling people’s bluffs – “reading” people. This can be done digitally and online too, but it is a totally different experience.

Flexibility

Board games are fully executed by human players. This allows for a certain kind of flexibility.

House Rules: Rules could be improved? Easily changed.
Games about Making Rules: Games like Hex Hex or 1000 blank white cards take it one step further by allowing the players to make up new rules or even design all game components and interactions.

Other Advantages

Components: Physical components are often cheap and dependable. Digital devices on the other hand need to be bought, and assuming that players have smartphones doesn’t hold true everywhere.
Available Space: Big touch screen are often very expensive, while producing a table-sized board game might not be exactly cheap, but still much cheaper.

Digital Advantages

Tutorial

In the board game world, learning a new game usually means reading a rulebook – or being taught by somebody who already knows the game. In the digital world, the learning companion can be the game itself. Digital games can enforce rules, teach when appropriate and react to players faults more easily. (Although Legends of Andor does a pretty good job at having a board game tutorial – inspired by digital games, no less.)

Control

In digital games, the experience is fully controlled by a processor: Input is taken and used as seen fit instead of direct interaction with the game pieces like in board games.

Setup Time: Even after learning the rules, physical games still have to be prepared manually. The worst you will usually get from a digital game is a bit of loading time.
Automatic Data Processing: Menial counting tasks and figuring out action results can be taken care of swiftly and automatically.
Information Display: The game can show predictions and context-sensitive information when needed.
Distance Calculation: Instead of moving in a visible grid or graph, movement can instead be by distance – and still does not need external tools like a ruler.
Real Time Play: Automatic data processing also allows real-time play since it can instantly compute outcomes and it can limit players action, for example via a cooldown delay or resource usage.
No Room for Player Errors: The game executes all the rules itself. If players haven’t understood a rule, it will still happen like it was originally intended.
Cheating Inhibition: While technical cheats are possible, those are far less casual than looking at enemy cards in a board game or switching pieces while an enemy has left the room briefly.
Impartial Judgment: Knowing everything that happens perfectly at any time and favoring nobody, digital games can easily judge results.
Artificial Intelligence: Processing power enables stronger and more interesting non-human enemies than board games.
Hidden State Processing: Hidden state can be automatically worked with in a truly hidden way. Considering a shared screen space, a game could still process what a hidden card does, for example mining one gold nugget per turn which the player could already use without revealing its source.
Hidden Actions/Communication: When a player has their own device available, they can take hidden actions with the game verifying that this action is actually possible – thereby allowing hidden actions without fear that another player cheats. In the same vein, this could allow communication between players without a third party knowing that this takes place at all, for example to form secret alliances and plan combined actions.
Sensors and Input Devices: Digital processing allows games to use sensors and interesting/complex input devices and integrate them into the gameplay.

Content

Storage Capacity: So many games on such a small disk.
Procedural Generation: Levels and playing fields can be created by algorithms on demand – with agency and configurable.

Presentation

Animation: Board games mostly have static visual elements that are moved around. Digital games can change or animate those elements according to actions and game state.
Sound Feedback: Obviously, the real world has sound feedback too, for example when placing a token – but here, digital games can play sound specific to what a token or action symbolizes, for example a cat token that meows when it gets a fish token.
Atmosphere: Changing visuals and added music can greatly increase the atmosphere for a game.

Logistics

Location: Tablets have much smaller screens than a board game would need. Suddenly, a big board game might be playable in a coffee shop.
Availability: No need to wait for a physical order to arrive – digital games can mostly just bought online and downloaded instantly.
Updatability: Game content and rules can be updated later via online updates.
Persistence: When a game takes too long to finish, it can be saved and later restored. Unlike most board games, that makes it very easy to move between playing locations too.

Online Play

Digital gaming devices are often connected to the internet which enables playing with people who are not sharing the same room. This enables playing with friends who cannot meet personally at the moment, but it also allows strangers to play together.

Real-time online play is obviously used in real-time games, although turn-based games often need everyone connected at the same time. On the other hand, the persistence of a server also allows asynchronous online play – players are not necessarily online at the same time, make a move, log out again and are notified once the other player made their move too.

The Prototypes

To find out whether having a physical/digital hybrid improves on gameplay, I made three game prototypes, each with a hybrid variant and a touch-only variant.

Finger-Flicking Game

The first prototype is a two-player versus flicking game with real-time scoring. Players flick discs into scoring areas, adding a new disk every few seconds. Sometimes it might be more advantageous to wait until the enemy goes first and then hit the enemy disk so it leaves the area it is in – and sometimes it might be better to quickly score in an easily accessible scoring area. The game ends after a fixed amount of time and the player with the higher score wins.

Master's Thesis - Finger Flicking Game

Watch this video on YouTube

Physical Part

The game uses physical tokens the player’s can flick, which I believed to me more engaging than a purely touch-based version because it adds tactile sensations and real-life interactions. I also thought the players might easier learn how much force they need to flick properly because they know naïve physics and get haptic feedback.

Digital Part

The main digital parts are a) the real-time scoring and b) the timer which allows the placement of new tokens. The game also uses visual feedback: The background is tinted in the currently winning player’s color and tokens which are scoring higher amounts emit bigger visual “waves”.

Spaceship Game

In the Spaceship Game, two players cooperatively manipulate a spaceship with attached satellites in real-time. The satellites have different turrets, shields or supporting structures. The goal is to survive as many waves of enemies as possible.

Master's Thesis - Spaceship Game

Watch this video on YouTube

Physical Part

The physical spaceship is a direct representation of the digital spaceship. Players get instant tactile feedback on their actions, and resistance and the feeling of tugging might make it easier to cooperate. Turning and moving should also be easier when working with a wheel instead of a touch screen.

Digital Part

The game simulates enemies coming at the player in real-time while also operating weapons, moving projectiles, resolving collisions and keeping track of hit points. This cannot be reasonably done in a non-digital tabletop version while keeping the real-time element.

Duel Game

The Duel Game is a turn-based two player versus game. Both players have five units with different roles: Berserker (does most damage), Guard (has most health, strong counterattack), Marksman (ranged attack), Ninja (can try to jump out of attacks and switch with a unit once per game) and Spy (can get direct information about enemy tokens). Their positions are secret and players also secretly assign power levels from 1 to 5 to them. In the following fight, players move and attack with the units, using their respective strengths and abilities, trying to find out what the enemy units are and to take them down. Once a player has lost all their units, the other player wins.

Master's Thesis - Duel Game

Physical Part

The tokens with the cardboard screens allow two players to play on the same screen space without any indirection and still have hidden information.

Digital Part

The game contains several parts would be very hard to remake in a purely physical tabletop version.

Firstly, the rule set of interactions and reactions is a bit complicated. Having this done automatically is quite helpful.

More importantly, the game contains several parts where you would need an external judge:

Fights are done in a doubly blind way: The attacking player knows a range of damage they can deal (for example 1-6), but they don’t know how much damage they did in this attack. On the other hand, the attacked player only knows that how much damage they took (for example 3), but not how much the opponent could have done.
The Spy can see information about enemy pieces without the enemy even knowing that they have been spied upon.
The Ninja can switch once with a friendly unit without informing the enemy player.

Test Results

Approach and Caveats

First off, this thesis did not have any budget or people to organize the search and testing, so it had only 12 probands in total. Additionally all the probands knew the author, with some even knowing the title of the thesis and a bit more information about it. I am fully aware that makes the results not very representative and less trustworthy, hence this caveat. The following is written in the hope that you still find it useful, if only for pointing in a general direction.

Each test session consisted of two players playing against each other. Many people played multiple games. A typical evaluation session looked like this:

The author of the thesis explains the game (5-10 minutes, depending on complexity)
The participants play a version of the game (5-20 minutes)
The participants separately fill out an AttrakDiff form for this version (5 minutes)
The participants play the other version of the game (5-20 minutes)
The participants separately fill out an AttrakDiff form for this version (5 minutes)
The participants separately answer the comparison questionnaire (5 minutes)

The AttrakDiff A/B test resulted in barely any difference between the two versions of each prototype, so I won’t mention it here.

In the comparison questionnaire, players rated 7 questions from 0 to 6, with “0” being “Hybrid” and “6” being “Touch-only”. The italic text explains the motivation of certain questions and was not part of the questionnaire sheet.

“Which version was easier to use?”
“In which version did you feel more in control?” (In games, less control does not always equal less ease of use. The Finger-Flicking Game might be easier to target in the touch-only version, which might make feel people more in control there, but the hybrid version might be easier to use due to less indirection of input.)
“Which version was more fun?”
“Which version was more interesting?” (This question tries to find out whether the hybrid version provides novelty value beyond pure gameplay.)
“Which version felt better?” (This question tries to capture whether the sensations provided by the tactile feedback add to the experience. It is deliberately vague to refrain from influencing people towards the hybrid version.)
“In which version did you feel closer to the other player?” (This tries to contribute to two questions: Do digital games feel more like playing “with the screen” instead of “with another player”? Does playing together on one screen in the hybrid version of the Duel Game make a noticeable difference?)
“If you had to play again, which version would you choose?”