Behavior is shaped by liturgies because, as Lewis stated, our inclinations are organized through trained habits, and habits are formed through rituals. And it is the shape of those rituals that cultivates the habits, because the form of the liturgy embodies certain values.
Allow me to illustrate. Imagine a dense forest separating two cities. In order to engage in commerce between these cities, merchants must pass through the forest. For the earliest of these merchants, this was a very difficult task, wrought with many mistakes and casualties. Eventually, though, over time and with experience, the merchants discovered the safest, quickest route through the forest. Once they did, they began to carefully mark the path so that they would remember the best way to go. Even then, each of these early journeys required careful attention to the markers so that they would not stray from the best way. Over time, however, their regular trips along that same route began to form a much more visible path to the degree that years later merchants hardly pay attention; they doze peacefully as their horses casually follow the heavily trod road. Here now is a well-worn path cut through the wood upon which travelers mindlessly pass from one city to the other. This path may seem mundane, but in reality it is embedded with values such as desire for safety, protection from the dangers of the forest, and conviction that this is the quickest way through. The snoozing merchants do not give thought to these values any longer, but the values are there nonetheless, and whether they know it or not, their journey has been shaped by those values. Those values are, as it were, worn into the shape of the path itself.
So it is with liturgies. Liturgies are developed over long periods of time, at first with very deliberate values in view, and those values are worn into the liturgies through regular use. And when people practice such liturgies, they are shaped by the values that have formed them, whether they recognize it or not.
Very simply, then, here is the fifth peg upon which my argument rests: liturgies are the repetitious practices people perform that then produce regular, habitual behavior—liturgies shape culture.