Conversation tree
Encyclopedia
A dialog tree or conversation tree is a gameplay mechanic that is used throughout many adventure game
s (including action-adventure game
s) and role-playing video game
s. When interacting with a non-player character
, the player is given a choice of what to say and makes subsequent choices until the conversation ends. Certain video game genres, such as visual novel
s and dating sim
s, revolve almost entirely around these character interactions and branching dialogues.
where all major outcomes from an event branch into their own chapters. Much like the game counterparts this story reconvenes as it progresses (as possible outcomes would approach n^m where n is the number of options at each fork and m is the depth of the tree).
The first computer dialogue system was featured in ELIZA
, a primitive natural language processing
computer program
written by Joseph Weizenbaum
between 1964 and 1966. The program emulated interaction between the user and an artificial
therapist. With the advent of video games, interactive entertainment
have attempted to incorporate meaningful interactions with virtual characters. Branching dialogues have since become a common feature in visual novels, dating sim
s, adventure game
s, and role-playing video game
s.
(or when a non-player character chooses to speak to them), and then choosing a line of pre-written dialog from a menu. Upon choosing what to say, the non-player character responds to the player, and the player is given another choice of what to say. This cycle continues until the conversation ends. The conversation may end when the player selects a farewell message, the non-player character has nothing more to add and ends the conversation, or when the player makes a bad choice (perhaps angering the non-player to leave the conversation).
Games often offer options to ask non-players to reiterate information about a topic, allowing players to replay parts of the conversation that they did not pay close enough attention to the first time. These conversations are said to be designed as a tree structure
, with players deciding between each branch of dialog to pursue. Unlike a branching story, players may return to earlier parts of a conversation tree and repeat them. Each branch point (or node) is essentially a different menu of choices, and each choice that the player makes triggers a response from the non-player character followed by a new menu of choices.
In some genres such as role-playing video game
s, external factors such as charisma may influence the response of the non-player character or unlock options that would not be available to other characters. These conversations can have far-reaching consequences, such as deciding to disclose a valuable secret that has been entrusted to the player. However, these are usually not real tree data structure in programmers sense, because they contain cycles as can be seen on illustration on this page.
Certain game genres revolve almost entirely around character interactions, including visual novel
s such as Ace Attorney and dating sim
s such as Tokimeki Memorial
, usually featuring complex branching dialogues and often presenting the player's possible responses word-for-word as the player character
would say them. Games revolving around relationship-building, including visual novels, dating sims such as Tokimeki Memorial, and some role-playing games such as Shin Megami Tensei: Persona
, often give choices that have a different number of associated "mood points" which influence a player character's relationship and future conversations with a non-player character. These games often feature a day-night cycle
with a time scheduling system that provides context and relevance to character interactions, allowing players to choose when and if to interact with certain characters, which in turn influences their responses during later conversations.
Another variation of branching dialogues can be seen in the adventure game
Culpa Innata
, where the player chooses a tactic at the beginning of a conversation, such as using either a formal, casual or accusatory manner, that affects the tone of the conversation and the information gleaned from the interviewee.
in the field of artificial intelligence
. In games such as Monkey Island, these conversations can help demonstrate the personality of certain characters.
Adventure game
An adventure game is a video game in which the player assumes the role of protagonist in an interactive story driven by exploration and puzzle-solving instead of physical challenge. The genre's focus on story allows it to draw heavily from other narrative-based media such as literature and film,...
s (including action-adventure game
Action-adventure game
An action-adventure game is a video game that combines elements of the adventure game genre with various action game elements. It is perhaps the broadest and most diverse genre in gaming, and can include many games which might better be categorized under narrow genres...
s) and role-playing video game
Role-playing video game
Role-playing video games are a video game genre with origins in pen-and-paper role-playing games such as Dungeons & Dragons, using much of the same terminology, settings and game mechanics. The player in RPGs controls one character, or several adventuring party members, fulfilling one or many quests...
s. When interacting with a non-player character
Non-player character
A non-player character , sometimes known as a non-person character or non-playable character, in a game is any fictional character not controlled by a player. In electronic games, this usually means a character controlled by the computer through artificial intelligence...
, the player is given a choice of what to say and makes subsequent choices until the conversation ends. Certain video game genres, such as visual novel
Visual novel
A is an interactive fiction game featuring mostly static graphics, usually with anime-style art, or occasionally live-action stills or video footage...
s and dating sim
Dating sim
Dating sims are a video game subgenre of simulation games, usually Japanese, with romantic elements. They are also sometimes put under the category of neoromance. The most common objective of dating sims is to date, usually choosing from among several characters, and to achieve a romantic...
s, revolve almost entirely around these character interactions and branching dialogues.
History
The concept of a dialog tree has existed long before the advent of video games. The earliest known dialog tree is evident in a story known as The Garden of Forking PathsThe Garden of Forking Paths
"The Garden of Forking Paths" is a 1941 short story by Argentine writer and poet Jorge Luis Borges. It is the title story in the collection El jardín de senderos que se bifurcan , which was republished in its entirety in Ficciones in 1944...
where all major outcomes from an event branch into their own chapters. Much like the game counterparts this story reconvenes as it progresses (as possible outcomes would approach n^m where n is the number of options at each fork and m is the depth of the tree).
The first computer dialogue system was featured in ELIZA
ELIZA
ELIZA is a computer program and an early example of primitive natural language processing. ELIZA operated by processing users' responses to scripts, the most famous of which was DOCTOR, a simulation of a Rogerian psychotherapist. Using almost no information about human thought or emotion, DOCTOR...
, a primitive natural language processing
Natural language processing
Natural language processing is a field of computer science and linguistics concerned with the interactions between computers and human languages; it began as a branch of artificial intelligence....
computer program
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
written by Joseph Weizenbaum
Joseph Weizenbaum
Joseph Weizenbaum was a German-American author and professor emeritus of computer science at MIT.-Life and career:...
between 1964 and 1966. The program emulated interaction between the user and an artificial
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
therapist. With the advent of video games, interactive entertainment
Interactive entertainment
The phrase interactive entertainment also known as video games refers to the business of producing and distributing products and services, or the products and services, of which the entertainment value can be influenced by users through direct feedback.-Origins:Although Hal Halpin claims credit...
have attempted to incorporate meaningful interactions with virtual characters. Branching dialogues have since become a common feature in visual novels, dating sim
Dating sim
Dating sims are a video game subgenre of simulation games, usually Japanese, with romantic elements. They are also sometimes put under the category of neoromance. The most common objective of dating sims is to date, usually choosing from among several characters, and to achieve a romantic...
s, adventure game
Adventure game
An adventure game is a video game in which the player assumes the role of protagonist in an interactive story driven by exploration and puzzle-solving instead of physical challenge. The genre's focus on story allows it to draw heavily from other narrative-based media such as literature and film,...
s, and role-playing video game
Role-playing video game
Role-playing video games are a video game genre with origins in pen-and-paper role-playing games such as Dungeons & Dragons, using much of the same terminology, settings and game mechanics. The player in RPGs controls one character, or several adventuring party members, fulfilling one or many quests...
s.
Game mechanics
The player typically enters the gameplay mode by choosing to speak with a non-player characterNon-player character
A non-player character , sometimes known as a non-person character or non-playable character, in a game is any fictional character not controlled by a player. In electronic games, this usually means a character controlled by the computer through artificial intelligence...
(or when a non-player character chooses to speak to them), and then choosing a line of pre-written dialog from a menu. Upon choosing what to say, the non-player character responds to the player, and the player is given another choice of what to say. This cycle continues until the conversation ends. The conversation may end when the player selects a farewell message, the non-player character has nothing more to add and ends the conversation, or when the player makes a bad choice (perhaps angering the non-player to leave the conversation).
Games often offer options to ask non-players to reiterate information about a topic, allowing players to replay parts of the conversation that they did not pay close enough attention to the first time. These conversations are said to be designed as a tree structure
Tree structure
A tree structure is a way of representing the hierarchical nature of a structure in a graphical form. It is named a "tree structure" because the classic representation resembles a tree, even though the chart is generally upside down compared to an actual tree, with the "root" at the top and the...
, with players deciding between each branch of dialog to pursue. Unlike a branching story, players may return to earlier parts of a conversation tree and repeat them. Each branch point (or node) is essentially a different menu of choices, and each choice that the player makes triggers a response from the non-player character followed by a new menu of choices.
In some genres such as role-playing video game
Role-playing video game
Role-playing video games are a video game genre with origins in pen-and-paper role-playing games such as Dungeons & Dragons, using much of the same terminology, settings and game mechanics. The player in RPGs controls one character, or several adventuring party members, fulfilling one or many quests...
s, external factors such as charisma may influence the response of the non-player character or unlock options that would not be available to other characters. These conversations can have far-reaching consequences, such as deciding to disclose a valuable secret that has been entrusted to the player. However, these are usually not real tree data structure in programmers sense, because they contain cycles as can be seen on illustration on this page.
Certain game genres revolve almost entirely around character interactions, including visual novel
Visual novel
A is an interactive fiction game featuring mostly static graphics, usually with anime-style art, or occasionally live-action stills or video footage...
s such as Ace Attorney and dating sim
Dating sim
Dating sims are a video game subgenre of simulation games, usually Japanese, with romantic elements. They are also sometimes put under the category of neoromance. The most common objective of dating sims is to date, usually choosing from among several characters, and to achieve a romantic...
s such as Tokimeki Memorial
Tokimeki Memorial
is a popular dating simulation series by Konami. It consists of 6 main games in addition to a large number of spin-offs. The games are notable in the dating sim genre for being highly nonlinear. Their nickname amongst their fans is the contraction TokiMemo....
, usually featuring complex branching dialogues and often presenting the player's possible responses word-for-word as the player character
Player character
A player character or playable character is a character in a video game or role playing game who is controlled or controllable by a player, and is typically a protagonist of the story told in the course of the game. A player character is a persona of the player who controls it. Player characters...
would say them. Games revolving around relationship-building, including visual novels, dating sims such as Tokimeki Memorial, and some role-playing games such as Shin Megami Tensei: Persona
Shin Megami Tensei: Persona
Shin Megami Tensei: Persona, known in Japan as is a series of role-playing video games developed and published by Atlus. The series is a spin-off of the Megami Tensei series which focuses on demon summoners. However, the Persona series centers around groups of teenagers who have the ability to...
, often give choices that have a different number of associated "mood points" which influence a player character's relationship and future conversations with a non-player character. These games often feature a day-night cycle
Persistent world
A persistent world is a virtual world that continues to exist even after a user exits the world and that user-made changes to its state are, to some extent, permanent...
with a time scheduling system that provides context and relevance to character interactions, allowing players to choose when and if to interact with certain characters, which in turn influences their responses during later conversations.
Another variation of branching dialogues can be seen in the adventure game
Adventure game
An adventure game is a video game in which the player assumes the role of protagonist in an interactive story driven by exploration and puzzle-solving instead of physical challenge. The genre's focus on story allows it to draw heavily from other narrative-based media such as literature and film,...
Culpa Innata
Culpa Innata
Culpa Innata is a third person point-and-click adventure game by Istanbul-based developer Momentum AS and published by Strategy First. The game, according to the developer, was inspired by Alev Alatlı's novel Schrödinger's Cat.-Gameplay:...
, where the player chooses a tactic at the beginning of a conversation, such as using either a formal, casual or accusatory manner, that affects the tone of the conversation and the information gleaned from the interviewee.
Value and impact
This mechanism allows game designers to provide interactive conversations with nonplayer characters without having to tackle the challenges of natural language processingNatural language processing
Natural language processing is a field of computer science and linguistics concerned with the interactions between computers and human languages; it began as a branch of artificial intelligence....
in the field of artificial intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
. In games such as Monkey Island, these conversations can help demonstrate the personality of certain characters.
See also
- Digital conversationDigital conversationA Digital Conversation is a scripted dialogue which takes place between a person and a computer via any digital medium from web browsers and PDAs to mobile phones and Interactive television.-Introduction:A Digital Conversation is scripted by a human, uploaded to a server where it can be accessed...
- Adventure gameAdventure gameAn adventure game is a video game in which the player assumes the role of protagonist in an interactive story driven by exploration and puzzle-solving instead of physical challenge. The genre's focus on story allows it to draw heavily from other narrative-based media such as literature and film,...
- Action-adventure gameAction-adventure gameAn action-adventure game is a video game that combines elements of the adventure game genre with various action game elements. It is perhaps the broadest and most diverse genre in gaming, and can include many games which might better be categorized under narrow genres...
- Sierra EntertainmentSierra EntertainmentSierra Entertainment Inc. was an American video-game developer and publisher founded in 1979 as On-Line Systems by Ken and Roberta Williams...