In this thesis I describe a method where an experience manager chooses actions for non-player characters (NPCs) in intelligent interactive narratives through story graph representation and pruning. The space of all stories can be represented as a story graph where nodes are states and edges are actions. By shaping the domain as a story graph, experience manager decisions can be made by pruning edges. Starting with a full graph, I apply a set of pruning strategies that will allow the narrative to be finishable, NPCs to act believably, and the player to be responsible for how the story unfolds. By never pruning player actions, the experience manager can accommodate any player choice. This experience management technique was first implemented on a training simulation, where participants’ performance improved over repeated sessions. This technique was also employed on an adventure game where players generally found the NPCs’ behaviors to be more believable than the control.

We have designed a simulation that can be used to train police officers. Digital simulations are more cost-effective than a human role play. Use of force decisions are complex and made quickly, so there is a need for better training and innovative methods. Using this simulation, we are measuring the degree of presence that a human experience in a virtual environment. More presence implies better training. Participants are divided into two groups in which one group performs the experiment using a screen, keyboard, and mouse, and another uses virtual reality controls. In this experiment, we use subjective measurements and physiological measurements. We offer a questionnaire to participants before and after play. We also record the participants change in heart rate, skin conductivity and skin temperature using Empatica device. By comparing the data collected from both groups, we prove that people experience more presence in the virtual environment.