Dialogue Trees

A dialogue tree presents the player with a short list of things to say, and the character’s answer opens another list. The magazines held here trace it from a 1985 Western in which every reply was a decision, through Sierra’s replacement of the text parser with a “conversation tree” in 1992, to the role-playing games of 1997-2000 where the tree became the game.

Fast facts

Earliest example here: Law of the West (Accolade, 1985) — four replies per encounter, each changing the other character’s mood (Zzap!64, 1986).
The phrase in print: “conversation tree”, Compute February 1993, of Sierra’s Quest for Glory I remake; “dialog trees”, Computer Gaming World, 1996 onward.
Two traditions: comedy (LucasArts: “no penalty for amusing answers”) and role-playing (Interplay: options gated by statistics).
The cost: “hundreds of characters and huge dialogue trees” — Jon Van Caneghem, 1999.

Choose a reply: Law of the West (1985)

Zzap!64 previewed Accolade’s Law of the West in January 1986 as “a game of ‘decisions’ and fast action”. The sheriff of Gold Gulch is approached by a series of characters, and for each line spoken to him four replies appear at the bottom of the screen. The saloonkeeper “[g]reets you with ‘Well, hello there big boy’, to which you may offer one of four replies, such as ‘Uh, hello, Miss Rose’, ‘Get off the street you painted Jezebel’, ‘Mind if I come up and visit you tonight?’ or ‘How’s the saloon business doin’ lately?’” Each answer leads to “four more possible replies for you to choose from. And so it goes on — unless you sufficiently annoy or scare a person enough for them to leave in a huff!”

The April 1986 review describes the replies as ranging from pleasant to aggressive, with the choice affecting the character’s mood, and reaches the verdict that has followed the technique ever since: “Unfortunately it soon proves [a] chore to play as the responses become predictable”.

From parser to conversation tree: Sierra, 1992

When Sierra remade Quest for Glory I with VGA graphics and an icon interface, Compute’s reviewer recorded the change in how the player talks: “To the chagrin of some and the delight of others, gone is the original text parser, now replaced with a icon-directed ‘conversation tree’ communication system. One general question leads to many additional, more specific choices of topics to discuss, which are added to the conversation tree.” The emphasis “is still firmly rooted in conversations and puzzles, not combat”. A speaking CD-ROM version was thought unlikely because of “the 80 actors and more than 6000 lines of conversation” that would need recording — the voice-acting cost that later shaped how many branches a game could afford.

Dialogue as comedy: LucasArts

Lucasfilm Games sold The Secret of Monkey Island (1990) on its talk. The advertisement in Computer Gaming World promised a game that “lets you trade insults with some of the saltiest seamen to ever sail the seven seas”, in which you “sling one-liners with a fast-talking used ship salesman, a sarcastic swordmaster, a wisecracking corpse, and a prisoner whose breath would stop a horse.” Scorpia’s preview in the same issue noted the natural way to play such a system: “you can always save the game, even in the middle of a conversation (handy if you want to see what reactions will come from making a smart remark or two).”

By the third game the approach was a recognised house style. Previewing The Curse of Monkey Island in 1997, CGW listed among the “fundamentals of the earlier games” that the new team had kept “dialogue trees with no penalty for amusing answers”, and its holiday guide promised “the most hilarious dialog trees in the business.”

Dialogue as role-playing: Fallout and Planescape: Torment

The other tradition ties the options offered to the character sheet. Jeff Green’s review of Fallout (Interplay, 1997) found that “every decision you make will have far[-]reaching repercussions” and that the game “rewards multiple play and experimentation.” It also found the seams. “The game’s many dialog trees don’t fully take into account the randomness of how you might play. Sometimes you can ask NPCs things you shouldn’t kn[o]w about yet. Characters you’ve encountered already wil[l] act like you’ve never met them every time you go back.” Killian, the Junktown store owner, “could never remember me, even after I rescued him from an assassin.”

Planescape: Torment (Black Isle Studios, 1999) went furthest. Thierry Nguyen’s review: “Most quests and conversations present different options based upon your character’s statistics.” “Every single dialogue or quest has multiple solutions based on your abilities. Combat is only absolutely necessary a few times; I talked/brained my way through three-quarters of the game the first time I played it”. The review warns that the game runs to about 800,000 words.

The same magazine had earlier placed Wing Commander IV as the reference point for dialogue with consequences, previewing Starfleet Academy in 1996 as a game “where dialog trees can affect what occurs later in the game.”

The designers’ problem

In January 1999 CGW put four role-playing designers together. Richard Garriott described the limit he had met in the Ultima series: “In the earlier days, we tried to mechanically simulate every possible reaction—getting exponentially harder and harder with less success. The more we tried, the more mechanical they seemed. Also, we were doing work that wouldn’t be appreciated. Now, we only try to simulate what is appropriate to a character.” Jon Van Caneghem explained why Might and Magic stayed flat: “M&M has the one-key spew. Hit one key and he spills everything he knows. The other extreme is to go through lots of layers. I go with the easy one as a rule because you’re going to have to deal with hundreds of characters and huge dialogue trees”.

A year later a preview of Deus Ex described a third path: “Dialogue with NPCs focuses on simple either/or responses, forgoing convoluted conversation trees, yet still playing a part in sculpting the overall course of the game.”

Branching conversation