Reality in a game can be described by the simulation of real things into a computer machines. Previously the games developed were artistically simplified representation of the simulation while the simulation was an attempt to represent as closely a real phenomenon in a serious form. Now the games have adapted the simulation and built games like the Flight Simulator to give a realistic experience to the gamers. Such games gives a gamer such feelings that most of them would never ever get to feel and experience in real life. It changes the personality of the user that makes the user feel that he/she is that character in the plane hence being directly involved in the game. (Crawford, 1998)
Games that don't have an inbuilt mechanism of simulating the reality by putting the gamer in first person as in games like Doom, Quake etc. build upon the character which the user plays. Usually a powerful story creates a strong character that has its own personality, moods and emotions. A game like Max Payne has a cinematic story that revolves around a main character and many different opponents. The personality is so strong in the game that the gamer feels the power of the moment in the game. The audio, video, graphics and interaction between players make the situation of the agent more realistic and believable. Another such popular game, Hitman, has a very strong character personality that is an emotionless killing machine targeting specific targets. These character agents show realistic emotions, situation based reactions, language and tone of voice etc, to make the gamer believe in the game setting. Building this factor into the game is extremely important as this is what the gamer looks for in every game.
Creating a main character is one thing, creating a non-playing character is a totally another. Today's computer games have such a high level of detail, high end graphics and realistic environments and characters that gamers can be led to believe that games are set within realistic settings while in the game. But according to Trinity College Dublin, the realistic illusion of the gamers is most often led into disappointment as soon as the gamer begins to interact with a computer controlled non-playing character either though conversation or attitude (Namee & Cunningham, 2003). Although the non-players look real and act real, but due to their lack of controlling intelligence, these characters lack the reality when the player to player interaction takes place. With the use of artificial intelligence and applying artificial neural networks in these characters, the TCD Game AI Project at the Trinity College to capture and add personalities, moods and relationships. (Namee & Cunningham, 2003)
The '-SIC' system is designed specifically for the development of non-player characters uses personality, mood and relationship models. A personality model uses the Eysenck's classification model which "plots personality across two orthogonal axes, introversion-extroversion and neuroticism-stability, allowing the creation of characters with personality types, such as aggressive, sociable and moody" (Namee & Cunningham, 2003). The mood model from Lang is used to measure agents' positive/negative moods and its intensity. The relationship model based on Wish's work plots the relationship of a character with respect to the "amount that a particular character likes another character, physical attraction,