Interactive Narrative: Structure and Present the Narrative Content in an Interactive Way

1. Narrative and Narrative Structures

Narrative plays an important role in human culture. It is the most common way for the human to exchange and process information. We use narrative to communicate, entertain and share knowledge with each other. Various ways of narrative exist in our daily life: We learn values from fairy tales and fables; We get aware of the happening important events from journalism; We have fun from movies, novels and computer games.

Prince defined in his book A Dictionary of Narratology that:

A narrative is a recounting of a sequence of events communicated by narrators to narratees.

It indicates that a narrative can be broken down into a sequence of events which have a continuant subject and constitutes a whole. Based on the different ways of structuring these events, there are two fundamental types of narratives: the linear narrative and the branching narrative.

1.1 Linear narrative

In a linear narrative, the sequence of events is narrated from beginning to ending without variations. Audiences cannot alter the way of how the story unfolds or ends. The linear narrative is the most common way of narrative in our life, for example, most of the movies, tv-series or novels.

1.2 Branching Narrative

In a branching narrative, the sequence of events is structured in a predefined set of alternative storylines. At certain events in the sequence, multiple choices are provided for audiences to choose and thus the storyline can be progressed into different outcomes. The structure of branching narrative can be represented as a branching story graph. Figure 1 shows a branching story graph for one of the CYOA books — The Abominable Snowman, in which nodes represent story plot points and arrows denote alternative choices of action that the player can choose.

Figure 1: A branching story graph for one of the CYOA books — The Abominable Snowman. (Made by Yu)

2. Interactive Narrative

What is Interactive Narrative?

According to Mark O. Riedl and Vadim Bulitko, Interactive Narrative is a form of digital narrative experience, of which the dramatic storyline can be dynamically created or influenced through audiences’ decisions and actions, either by issuing commands to computer-controlled characters or directly manipulating the fictional world state.

Audiences in the interactive narrative systems often take the role of the protagonist to influence and unfold the storyline. They can also be a disembodied observer who observes the storyline from a 3rd person’s perspective but is able to interact with characters and influence the storyline.

Why involve interactions into narrative?

The interactive narrative is not a fight against the linear narrative, but is to provide audiences with a new way to participate in the story. The most significant difference between the interactive narrative and the linear narrative is that the audience has a satisfying power to take meaningful action and see the results of the decisions and choices. This power is defined as Player Agency by Murray and it provides audiences with an immersed and engaging narrative experience, which is one of the key elements of interactive entertainments such as games and interactive dramas.

The interactive narrative can also be used for serious purposes such as interactive tutoring and skill training. Previous research on cognitive psychology suggests that narratives can benefit communication, social interaction, and learning, etc. Combining narrative and interactions can not only make the educational process engaging but also adjust the learning pace based on the individual differences and create different scenarios for the learning purpose. For example, Rowe et al. proposed a problem-based inquiry learning system in the interactive narrative environment for science, technology, engineering, and mathematics (STEM) education; Riedl et al. employed various interactive scenarios to create realistic contexts for skill practice; And Interactive Narrative can also be used to teach social skills and social conventions to children and young adults in a safe environment.

Different types of Interactive Narrative systems

Mark O. Riedl and Vadim Bulitko further mapped the landscape of different types of interactive narrative into three dimensions: authorial intent, virtual character autonomy, and player modeling, as shown in Figure 2.

Figure 2: The landscape of different types of interactive narrative

The X-axis represents the Authorial Intent, which refers to that in how much degree the interactive narrative system is constrained by the author’s storytelling intent. The left side of the axis are systems that are highly constrained by human author’s intent, which means the narrative content is almost fully scripted by the human author, including the main plots and branching plots. On the right are systems are less constrained by human author’s intent. The author provides more general intent in this type of system, for example by defining the characters, the relationships of the characters, the environment, the situation which the narrative must address, etc.

The Y-axis represents the Virtual character autonomy. It refers to how much autonomy the computer-controlled characters in the fictional world can have The top side of the Y axis means the systems in which computer-controlled characters will act consistently under the overarching narrative needs, which normally include the author’s intent and the audience’s preference. The bottom side of the Y axis means the systems in which computer-controlled characters will act consistently with their own character and settings.

The Z-axis represents the Player modeling. It refers to that in how much degree the interactive narrative system attempt to learn about the individual differences of the audiences. Audiences have different preferences when they make decisions can take actions. The player modeling attempt to capture the pattern of audiences’ interactive behavior in the narrative experience and model their preferences. The modeled preferences are used to predict and recommend the preferred submissive plot to the audiences.

The left-up corner of the landscape represents the interactive systems similar to the traditional CYOA books, in which the storylines are fully pre-scripted by human authors and the characters act continuously based on the pre-defined storylines.

The right-bottom corner of the landscape represents the interactive systems in which pre-defined characters are spread in the different environments and situations. These characters act continuously based on their own characters and settings. Audiences encounter the characters and trigger events. The sequential interactions between audiences and computer-controlled characters from the storyline. This kind of interactive narrative systems is often referred to as the emergent narrative.

There are also other types of interactive narrative systems existing between the CYOA systems and emergent narrative systems. They share hybrid characteristics from these two systems.

3. How to structure the Interactive Narrative?

An interactive narrative is generally a digital form of branching narrative, and the structure can also be represented as a branching story graph. Figure 3 shows a simple branching story graph, in which nodes represent story plot points (denoted by numbers) and arrows (denoted by letters) denote alternative choices of action that the player can choose.

Figure 3 A simple branching story graph (Made by Yu)

For the CYOA-liked Interactive Narrative systems, the alternative choices (arrows in Figure 3) and endings (plot point 8 and 9) are pre-defined by the human author. Therefore the numbers of branching storylines are limited and each outcome of the storyline is predictable. In the case of Figure 3, there are 5 possible storylines and they are {1,2,3,4},{1,2,3,5,8}, {1,2,3,5,9}, {1,2,6,5,8} and {1,2,6,5,9}. The content in each plot point is a complete event scripted by authors in advance, including the characters, environments, conflicts, dialogues and other narrative elements.

For the Emergent Narrative systems, the structure can be considered as a combination of multiple branching structures discretely distributed in a larger graph (see Figure 4). Each branching structure represents a branching storyline can be triggered by a certain character or condition. The front and clear branching storyline in the figure means the active storyline which the audience is experiencing, while the other blurred ones are storylines can be triggered by other conditions. Audiences encounter a computer-controlled character when they explore the fictional world and then start a branching storyline.

Figure 4 An illustration of the structure of Emergent Narrative systems

The content in each plot points is not fully pre-scripted stories but only settings which can be used to generate storylines. These settings can be characters, certain conditions, certain environments, conflicts, etc. In this structure, the storyline is naturally emerged based on the author defined settings and the choices audiences make. The storyline has branching outcomes because of audiences’ choices, but the numbers of branchings and outcomes of the storyline are not predictable, even for the authors who define the settings.

Interactive narrative systems between the CYOA systems and emergent narrative systems have a mixed structure of the two ones mentioned above.

4. Present the Interactive Narrative to the audiences

Now assuming that the content and structure of the Interactive Narrative are ready, the next question is how to present the content to the audiences. To answer this question, firstly we can have a look of the information seeking behavior of the audiences to determine their information needs.

4.1 Information Seeking Behavior of the audiences

The polar bear book uses the fishing metaphor to illustrate audiences’ information seeking models. Three of them can also be used to describe the information seeking behavior when the audience experience the interactive narrative. They are:

  1. The perfect catch: Audiences know exactly their goals in the interactive narrative, for example, saving the princess, beating the villain or being a good guy. And their choices are consistently based on their goals.
  2. Lobster trapping: Audiences don’t have a specific goal and more like to explore the storyline. And if the outcome meets their preference, then the narrative is good enough for them. For example, an audience prefers to have a happy ending, and any possible happy endings in the interactive narrative he/she is experiencing is good enough for him/her.
  3. Indiscriminate driftnetting: Audiences want to explore all the possibilities and achieve every ending in the interactive narrative.

4.2 Information needs of the audiences

From the fishing metaphor, we can conclude the following information needs of audiences in interactive narrative:

  1. Knowing which storyline leads to the desired narrative experience. (from The perfect catch and Lobster trapping)
  2. Knowing if they are in the right storyline to the desired narrative experience. (from The perfect catch and Lobster trapping)
  3. Knowing how to alter to another storyline if audiences feel they are not in the desired narrative experience or want to explore another storyline. (from The perfect catch and Lobster trapping and Indiscriminate driftnetting)
  4. Knowing how many storylines in total exist. (from Indiscriminate driftnetting)

A hidden need here is to balance the guiding provided to the audience and the audiences’ enjoyment of exploring the narrative themselves. Audiences enjoy explore different possibilities and gradually have a broader view in the fictional world. So how to gently guide the audiences while reminding their fun of exploring is a key element to improve their narrative experience.

In the following sections, some solutions addressing these information needs will be discussed.

4.3 Chapters and Navigation

For the CYOA-liked Interactive Narrative systems, a common solution to meet information the needs 2, 3, 4 is to divide the full storyline into chapters and provide a navigation system.

As we can see from Figure 1 in section 1.2, the structure of the interactive narrative system can be big and complicated. Dividing the whole storyline into chapters can prevent audiences from being overloaded by too many options and branchings. The chapters are usually organized adhering to a particular pattern, such as the Aristotelian dramatic arc (see Figure 5)to create the rhythm and the tension in the narrative. The title of each chapter also can imply what gonna happen in the chapter to let the audiences have a clearer goal while not be fully spoiled.

Figure 5 The Aristotelian dramatic arc (Made by Yu)

The division of chapters also provide the audience with a milestone to check where are they, are they in the desired storyline and to adjust their tracks. This is usually done by a navigation system. The navigation system mostly will be revealed after the audiences fully experience one branching in this chapter for the purpose of balancing the guiding provided to the audience and the audiences’ enjoyment of exploring the narrative themselves. Figure 6 shows an example of the navigation system from the game Detroit: Become Human.

The navigation system represents the branching story graph and shows all the possible branchings in this chapter. It states clearly which storyline the audience has experienced and which ones are not. It also indicates which plot points the audience can navigate back to make a different choice and alter the branching.

4.4 Quest Log

For the emergent narrative system, a more common solution is to use the Quest Log system to meet the information needs 2, 3. In this type of interactive narrative system, each of the storylines is shorter and has a simpler structure. But the challenge is that there are some many storylines existing in the fictional world and audiences may get lost and overwhelmed by too many possibilities. A Quest Log system is used to indicate audiences which storyline they are experiencing, and to provide the context of what to do next. Figure 7 shows an example of the quest log system from the game The Legend of Zelda: Breath of the Wild.

Figure 7 An example of the quest log system from the game The Legend of Zelda: Breath of the Wild

Normally audiences will experience more than one storyline at the same time in this kind of narrative system, and for the active storyline (In this case is The Ancient Rito Song which is indicated by the yellow dot after the name) the quest log system will provide more related information. Audiences can switch the active quest to change the focus of different storylines.

4.5 Context and Labelling

For the information needs 1, the common solution is to provide enough context to let the audience have enough clues to make confident choices and having a consistent and representative labelling system.

When audiences experience and progress the storyline, they do not know what will happen in future when they make choices and take actions. They usually select options based on a variety of local clues, such as the words in the dialogues, contents in previous plot points, the environment, the name of the chapter or the quest, etc. So when the audience chats to other characters’ or exploring the environment, they should be provided with enough context which indicates the current situations and possible options. This can also provide the audience with an achievement of problem-solving and the freedom and confidence of making the choice based on their own judgement.

The consistent and representative labelling system is especially important in the options for audiences to select. Due to the limited number of words, options are often represented in short phrases or few keywords. Make these keywords fit in the context and correspond to the following plot progression can indicate audiences where the option generally leads to. Figure 8 shows a labelling system from the game Detroit: Become Human, which used keywords to represent the following actions the audience controlled character is going to take.

Figure 8 An example labelling system from the game Detroit: Become Human

4.6 Drama manager

Drama manager is an intelligent approach to meet the information needs 1. A drama manager is an intelligent, omniscient agent behind the system, audiences normally can not interact with it. It tracks the audience’s behaviors and choices during the narrative experience and models the audience’s preference. Then it predicts what the audience’s preferred narrative experience and intervenes the fictional world to drive the narrative forward to his/her preferred narrative. Common ways for the drama manager to intervenes the fictional world can be directing a computer-controlled character to give hints to the audience, causing certain plot points have higher possibility to occur, or temporarily denying certain plot points from occurring.

The modeling process of audiences’ preferences can be implemented using the Collaborate Filtering Algorithm. Figure 9 illustrates how the CF algorithm works in a simplified way. In the figure, these two guys are considered that they share similar preference patterns because they both have positive ratings towards salads and pizzas. And then due to the guy on the right gives a positive rating to cokes, the CF algorithm will suppose the guy on the left also likes cokes and recommend coke to him. It works in a similar way when recommending the plot points in the interactive narrative systems to audiences.

Figure 10 How the CF algorithm works in a simplified way

This approach requires to collect audiences’ feedback to model their preferences, the easiest way is to let audiences vote their preferences of plots presented after the choice. Then based on the rating, the CF algorithm models users preference and predict users’ preferred plot based on similar audiences’ preferences. After that, the drama manager will intervene to drive the story forward to the preferred narrative.Yu’s PhD dissertation has a more comprehensive introduction of how the drama manager with the CF algorithm works in the interactive narrative systems.