It’s 2017, and conversational interfaces (people talking with machines the same way they talk to other people) are everywhere. Siri has become a household name. Taco Bell lets you order tacos over Slack. A chatbot lawyer can help you get out of your parking tickets. MasterCard is allowing people to manage their credit cards via Facebook Messenger.

It feels like we may spend more time talking to computers than to one another in just a few short years.

How did we get to this point? Where did the conversational interface originate?

Like most things in computer science, everything old has become new again. The predecessor of the modern conversational interface, “interactive fiction,” has been with us for more than 40 years. By taking a look at interactive fiction, we can better understand what makes conversational interfaces effective, as well as the lessons that interactive fiction developers have learned.

Humble beginnings

The first true conversational interface arguably dates to 1975, when Will Crowther, an engineer who worked on router code for the ARPANET, combined into a computer game for his daughters his two favorite hobbies — exploring Mammoth Cave National Park and playing Dungeons & Dragons. The result, Colossal Cave Adventure (“Adventure”), spawned a new genre of computer game.

In Adventure, the computer presents the player with a text description of where their character is standing, followed by a prompt. The player responds with a one- or two-word phrase of what they want their character to do — get lamp, go north, etc. The computer parses the player’s input and presents a new piece of text to tell the player what has changed.

A skilled player could, by typing the correct series of phrases, guide their character through an elaborate cave network, collect five treasures and return them to the house above ground. At the end, the player’s commands, combined with the program’s output, would form a full transcript of the “adventure” that could be read as a story.

The game spread through college campuses via the ARPANET, and was incredibly popular. By one estimate, the time spent on the game “set the entire computer industry back two weeks.”

The culture around Adventure, groups of people meeting late at night in campus computer labs, even inspired the first doctoral dissertation about a video game, “Interactive Fiction: The Computer Storygame Adventure” by Mary Ann Buckles. This work is part programming deep-dive, part literary analysis and part anthropological study. Adventure became a touchstone of computer culture and for many years defined what “video games” were.

Interactive fiction exploded in the 1980s, fueled by the success of Infocom, a company best known for the Zork series of games. Infocom was able to develop for a wide variety of systems by building one of the first commercial virtual machines for home computers (“Z-Machine”).

In an environment where each year’s new graphics technology was leaps and bounds beyond that of the year before, text adventures were comparatively ageless, which extended their sales even further. Once the computer industry consolidated to the graphically rich PC and Mac, though, Infocom went bankrupt, and interactive fiction as a commercial enterprise died soon after.

New directions

Devoted fans of the genre were not ready to let go. Enthusiasts built their own interactive fiction development platforms. The two primary development environments, TADS (“Text Adventure Development System”) and Inform, formed the core of an interactive fiction renaissance. The interactive fiction community grew again around newsletters like SPAG and competitions like IFComp, existing just under the radar of the wider video game community.

These new tools allowed anyone with a basic understanding of programming to make their own interactive fiction games, including games significantly more complex than Adventure. The parsers built into TADS and Inform can understand multi-word phrases with words of any length, opening up a number of conversational possibilities. Where an Adventure player might be limited to fight a troll, a more peace-loving player of TADS or Inform could ask a troll about his mother, give fresh-baked bread to a troll or even just say hello to a troll.

By expanding the scope of player inputs, TADS and Inform expanded the very definition of what an interactive game could be. Providing sophisticated characters for players to interact with in a more human-like fashion than ever before enabled interactive fiction to serve as a platform for role-play.

Full circle

TADS and Inform have continued to evolve. While interactive fiction has expanded to the internet, most developers of conversational interfaces are implementing systems that are a poor fit for the interactive fiction model. They are often one-off interactions (ordering tacos) as opposed to persistent world simulations (collecting treasures underground over several play sessions).

Yet it would be a mistake to write off interactive fiction entirely. We can learn from its history, both the techniques that led to success and the stumbles along the way. Here are a few of those lessons to use in your next project:

Portability is powerful

Infocom’s success rested in large part on its ability to produce games for every system available. Infocom games were entirely presented as text, and text is readable by any kind of computer system. As Graydon Hoare said, always bet on text, because “the breadth, scale and depth of ways people use text is unmatched by anything.”

For conversational interfaces, text enables experiences that traditional graphical user interfaces cannot provide. Users gain the ability to save transcripts of their interactions; to share them easily with friends; to translate them, annotate them or search them. Creators, meanwhile, gain powerful debugging and analysis tools because computers can sift through text much more easily than videos of user interaction. If you are debating whether or not to develop a conversational interface for your product, focus on these areas of strength as you make your decision.

Beware the ELIZA effect

In 1966, a computer program named ELIZA made a splash in computing circles. Predating Adventure by nine years, it instructed the user to tell it their troubles, and responded as a therapist of sorts. Internally, the program was unsophisticated, latching on to key words in the user’s input and reformulating them into questions, or asking generic open-ended questions as a default. ELIZA had no memory of anything the user had previously typed, and most of the interaction could be re-created by rolling dice and consulting a list of phrases.

These new tools allowed anyone with a basic understanding of programming to make their own interactive fiction games, including games significantly more complex than Adventure. The parsers built into TADS and Inform can understand multi-word phrases with words of any length, opening up a number of conversational possibilities. Where an Adventure player might be limited to fight a troll, a more peace-loving player of TADS or Inform could ask a troll about his mother, give fresh-baked bread to a troll or even just say hello to a troll.

By expanding the scope of player inputs, TADS and Inform expanded the very definition of what an interactive game could be. Providing sophisticated characters for players to interact with in a more human-like fashion than ever before enabled interactive fiction to serve as a platform for role-play.

Full circle

TADS and Inform have continued to evolve. While interactive fiction has expanded to the internet, most developers of conversational interfaces are implementing systems that are a poor fit for the interactive fiction model. They are often one-off interactions (ordering tacos) as opposed to persistent world simulations (collecting treasures underground over several play sessions).

Yet it would be a mistake to write off interactive fiction entirely. We can learn from its history, both the techniques that led to success and the stumbles along the way. Here are a few of those lessons to use in your next project:

Portability is powerful

Infocom’s success rested in large part on its ability to produce games for every system available. Infocom games were entirely presented as text, and text is readable by any kind of computer system. As Graydon Hoare said, always bet on text, because “the breadth, scale and depth of ways people use text is unmatched by anything.”

For conversational interfaces, text enables experiences that traditional graphical user interfaces cannot provide. Users gain the ability to save transcripts of their interactions; to share them easily with friends; to translate them, annotate them or search them. Creators, meanwhile, gain powerful debugging and analysis tools because computers can sift through text much more easily than videos of user interaction. If you are debating whether or not to develop a conversational interface for your product, focus on these areas of strength as you make your decision.

Beware the ELIZA effect

In 1966, a computer program named ELIZA made a splash in computing circles. Predating Adventure by nine years, it instructed the user to tell it their troubles, and responded as a therapist of sorts. Internally, the program was unsophisticated, latching on to key words in the user’s input and reformulating them into questions, or asking generic open-ended questions as a default. ELIZA had no memory of anything the user had previously typed, and most of the interaction could be re-created by rolling dice and consulting a list of phrases.