Adaptive Music

Patterns

The human brain is fantastically adept at recognizing all kinds of patterns. The human brain is fantastically adept at recognizing all kinds of patterns. The human brain is fantastically adept at recognizing all kinds of patterns. (I bet you skipped at least that last sentence without even reading it.) Patterns in any medium involve some form of repetition, and have a certain aesthetic appeal. Unfortunately, with over-repetition comes boredom. Repetition provides unity and cohesiveness; variation provides interest. This is always a delicate balance!

	Patterns

What is interesting about these examples is how important scale is when balancing cohesiveness and interest. For example, when your brain looked at the boring pattern, it saw repeating "t"s. Boring. When it looked at the less boring pattern, it saw the same repeating "t"s; however, its interest was held by the larger grouping patterns that began to emerge. Spend some time with each of the patterns and think about the meaning of "t" in each one. I'm serious! There is a lot to be learned from these simple examples.

Boring Adaptive Poetry
Think way back to "Adaptive Word Texture" examples. Which adaptive poem would get boring faster? Most definitely it's the "Adaptive Word Texture With Meter and Rhyme" version. In that example, two patterns (meter and rhyme) repeat constantly without variation. By the second couplet, the pattern has become recognizable. By the third, it has become predictable. By the fourth, it begins to become tedious.

One might argue that the "Adaptive Word Texture" poem's structural organization is in fact more repetitious and therefore more tedious. After all, it's essentially just word, word, word, word, word… Why isn't this the case? In the first version the simplicity of the pattern works in its favor. It's unobtrusive -- it's basically a non-pattern. It doesn't distract from the interesting unpredictability of what the next word might be. By contrast, the higher level structural patterns in the second version engage the part of the brain that pays attention to higher level structural patterns -- and becomes bored with them. In this case, the (repetitious) structure dominates the (non-repetitious) content. This unbalance is due in part to the fact that our content only works at the word level, while the patterns (and the brain) are working at the phrase level.

Adaptability at the Phrase Level
The problem with word textures is that they are extremely limited in terms of actually expressing ideas. Compare "danger fear shadows lurking seal evil danger" (from "Adaptive Word Texture") to "the enemy could attack at any moment." The first "sentence" is a pseudo-random collection of symbols. The second uses syntax to combine symbols into a coherent thought. It actually says something. (And you thought syntax was only important for programmers!)

What happens when we try to write an adaptive poem that actually communicates something at the sentence (phrase) level? A logical place to start might be with a sentence texture. This will work in much the same way as the word texture example, except that we will use four lists of complete sentences.

Example: Adaptive Sentence Texture

(SPOOKY cue) This place is really scary. Is that shadow moving? It's really dark here. The enemy could attack at -- (COMBAT cue) Hot blood spurts like a fountain! The fighting is fast and furious! The violence is incredibly intense and visceral! Teeth are gnashing and flippers are slashing! The fighting is fast and furious! Seal bits are flying everywhere!

An important thing to consider is the production cost of sentence texture compared to word texture. A word list that is twenty elements long requires only twenty words. A sentence list that is twenty elements long requires more than one hundred words! Plus, the production of a sentence involves a process of composition.

Variety at the sentence level requires a bigger budget than the same amount of variety at the word level. On the other hand, a single sentence covers more "ground" in terms of words and time. The "Adaptive Sentence Texture" example used far fewer elements than the"Adaptive Word Texture" example, but was just as long. In terms of pure variation over time, perhaps fewer sentences are required.

Another issue is that complete ideas demand more attention from the player. The danger is that instead of enhancing gameplay, we're going to start distracting the player from it. There's an old saying among film makers: "The best soundtrack is the one you never hear." (You should be feeling it instead.) The idea is that if you notice the music, it's because the composer's done something wrong. Well, the same goes for adaptive poetry. We want the player to respond on an emotional level, not an intellectual one. Complete sentences are dangerously high level.

Lastly, sentence texture is a lot less flexible than word texture. It takes longer to state an idea than it does to state a word. Our "Adaptive Word Texture" example could switch moods literally in midstream. However, when dealing with adaptive structures at the phrase level, we're suddenly faced with logistical and creative concerns about what to do when the game mood changes in mid-sentence. How do we make a smooth and effective transition?

Transitions

That was a pretty good transition, wasn't it? It was even at a higher structural level than mere sentences, or even paragraphs. I changed sections almost seamlessly! OK, not so impressive. I already knew where I was going, and timing my arrival wasn't critical. So, I was able to compose my sections so that they fit together just so.

In adaptive poetry, timing is critical. In order to enhance the mood, changes have to happen with the mood. If cues are delayed, even by a second, they aren't contributing to the emotional experience of a game event. They become their own distinct event, separate from the associated game event - which the player's brain will already have had time to process. Poetry mood changes have to happen on time!

In the "Adaptive Sentence Texture" example, this wasn't a big deal. When the seals sprung their surprise attack, it made sense to suddenly interrupt the previous mood. Ending a combat mood might be more complicated, though. Imagine that the sentence "When will the carnage end!?" is one of our combat list elements. Imagine that Captain Brave-O strikes down his last opponent midway through the playback of this particular sentence. We want to switch to victory poetry, and we don't want to be late. We also don't want to be awkward. One way to address this situation is to compose transition versions of the combat sentence. If the mood changes midway through the statement, we continue smoothly with the transition version.

	Adaptive Word Texture with Meter and Rhyme

 

Immediately, the cost of this approach should be obvious. Each element of the sentence list will require similar treatment if the transition to victory is to be possible at any time. Additionally, transitions to other moods may be necessary. ("When will Captain Brave-O be deader than this?") On the other hand, it does what it's supposed to de very well. What more could we ask for?