Shigeru Miyamoto, the father of the Mario and Zelda franchises, tells us that he designs his games around a series of specific emotional experiences. Console manufacturer Sony have christened the PlayStation 2's CPU the emotion engine'. Clearly the gaming community understands the importance of emotion in games, so why do most games offer the player such a shallow emotional play experience?
The reason is partly due to the relative immaturity of the games industry. Whereas the film industry has a mature and well developed structure for how the auteur might evoke tears in the eyes of the audience, the digital games industry is still in the process of writing the rule book.


With digital gaming being a visual medium, you might expect techniques for eliciting emotion to be transferable across media. Unfortunately, this is often not the case. The film director has complete control over the image appearing on the cinema screen - the camera angle, the sequential order of each scene, and the pacing of a scene. In contrast, the game designer hands control of such things to the player. The player will choose the camera angle best suited to getting Mario across the tight rope, as well as the direction and pace at which the game progresses.


Interactive media needs to find their own rules for supporting emotion in games, and they have a couple of neat tricks which set them apart from the competition.
Evoking an emotional response in the player
The interactive nature of digital games provides new and very different possibilities for eliciting emotions. For example, whereas the movie goer simply watches the narrative world unfold, the game player gets to interacts with it - and each environment has the potential to evoke a different emotional response. For example, a large building with towering marble pillars is generally considered much more imposing and makes people feel smaller and more uncomfortable than a small room with a sofa and a blazing wood-fire.
At Glasgow Caledonian University we are currently looking specifically at those environments which are renowned for producing supernatural experiences.

By modelling and adapting reputedly haunted places in Edinburgh, UK we have been able to create game environments which evoke ghostlike experience for approximately 60% of people who experience it. Reported experiences include the feeling a ghost breathing on the back of their neck, the feeling of another's presence in the virtual world, suddenly feeling cold on entering a specific room, and seeing things and hearing things that are not pre-programmed into the environment.
Recognising the emotional state of the player
There are various tools which can be used to determine the affective state of the game player. Researchers at MIT in Dublin have been investigating the use of galvanic skin response (GSR) to determine a player's state of arousal. Relax-to-Win' is a therapeutic game where the player's level of relaxation controls the speed of a racing dragon. At the Interactive Institute in Stockholm, the player's brain activity is being measured by an electroencephalogram (EEG) in the game Brainball'.

This is a two player game where the direction of a steel ball is determined by each player's ability to meditate.
An alternative method for recognising emotions using traditional console equipment is currently being investigated at Glasgow Caledonian University. Already, experiments have found that the affective state of the player can be determined by how they use the gamepad. Not only does the pressure of button depression indicate the level of player arousal, but also the rate at which a button is pressed and eventually released indicates the emotion felt by a player.


There are three major benefits to be gained from knowing the affective state of the player:
1. DYNAMIC CONTENT
Like the traditional campfire storyteller who adapts their story to the listener, the game designer can tailor the game content to suit the audience's emotional response. This is particularly relevant when the player chooses to pause the game for a period of time to eat, to answer the telephone, or to sleep, etc. When the player returns to the game they are unlikely to be in the same affective state as when they stopped the game. Therefore they are not going to fully experience the fear created by the sudden appearance of a zombie crashing through the stained-glass window.
However, by monitoring the affective condition of the player, the game designer can renegotiate the best path to each emotional climax.

This means that the player is always in the most appropriate state of mind to appreciate the game content. For the player to fully appreciate the sudden appearance of the zombie, it would be better to again build up the suspense and wait until the player is suitably apprehensive.
2. COMMUNICATING AFFECTIVE STATE TO 3RD PARTIES
Emotional involvement with our opponent plays a large role in our enjoyment of a game. For example, it is much more enjoyable to beat a smug, confident opponent than a nervous newbie with no knowledge of how to control their avatar.

With the arrival of online gaming it is often the case that a player's opponent is not physically present, thus diluting the social experience of multiplayer gaming. However, if the software could determine the player's affective state, an on-screen persona could be adapted to reflect the player's emotional state.
3. AFFECTIVE GAME-MECHANICS
Knowing the affective state of the player allows for novel game mechanics based around the player's emotions. An example of such can be found in Zen Warriors, a game currently in pre-development at Glasgow Caledonian University. Zen Warrior is a fighting game where, to perform their finishing move, the player has to switch from fast paced aggression, to a Zen-like state of inner calm.


These are exciting times. Games have taken the huge aesthetic leap from two dimensions to three dimensions. The next evolutionary step is for games to elicit deeper and more varied emotion in players. And we are still only writing the first chapter of the rule book.
--
Jonathan Sykes
Jonathan Sykes currently heads the eMotion Laboratory at Glasgow Caledonian University, where he investigates emotional engagement with technology.