[How can incorporating real-world behavior change the fundamental play of games? The developers behind games that delve into this question, such as The Sims 3, SpyParty, and Facade, answer this question.]

Playing is behaving. From childhood experimentation and role-play to the competitive simulations of adults, it's impossible to separate even the most abstract forms of play from human expression. Yet video game design is dominated by the perceived need for win conditions.

If an interaction can't be parsed into passing or failing it can't be counted as fun. Without the threat of failure there is no fun. Yet, it's not victory that drives the invented play of kids on a playground, nor friends laughing over an inside joke.

Video games built around behavior aren't often given the same attention more competitively oriented games are, but they're no less important a part of the industry.

Games like The Sims 3, Heavy Rain, Nintendogs, Façade, Animal Crossing, and Harvest Moon are all made for the pleasures of expression. These are games played for their creative experiences more than their victory conditions.

Recent years have seen a wall built up to separate hardcore and casual games. It's an arbitrary distinction used to diminish games a person doesn't like by shoving them into a category defined by non-seriousness. A truer way of looking at video games is on a spectrum defined on one end by competitive games and on the other by purely expressive ones.

There are many subtle shades in between -- Mass Effect's conversation system, Call of Duty 4's nuke sequence, Spore's creature creator, Nintendogs' loyal competitions. Indeed, as with earlier media, the most impressive works often blur distinctions between genre and find ways to join seemingly opposite ideas.

There has been much inquiry into objective design, competitive incentive, and metering the rate of achievement, yet thinking about non-competitive ways of creating expression is a blindspot for many in the video game industry. What follows, then, is a survey of how and why expressive behavior can be used in game design, both as a means to a competitive end and a playful end unto itself.

A Sweeping Surprise

"When you're making the base game, you're trying to capture the essence of everyday life in a way that will appeal to nearly everyone," Charles London, creative director of EA's The Sims Studio, told me.

"Basic things, like sleeping, eating, being romantic, or watching TV, are very high on the list; without those, there's really no core to 'everyday life' around which to wrap more exotic content."

The Sims series is the alpha and omega of non-competitive games. You can't beat a Sims game, but you can spend hundreds of hours experimenting with its web of interrelated behaviors. The reward for playing comes from small surprises and moments of simpatico rather than increasing difficulty curves.

"We rarely design activities or interactions for our Sims without having an overarching theme, like seasonal winter snow play, or going out to nightclubs and restaurants, or learning to be a firefighter," London said.

"Once we've identified the activities that are core to making the theme believable, the constituent behaviors come into pretty sharp relief. The idea is to make them as modular as possible, so that the player has as many chances to be surprised by what happens as we can give them."

The Sims' use of indirect control is crucial to its mix of familiar action and unexpected results. It allows the player to plan sequential events instead of focusing on repetitive action. Because the player can't immediately affect the action they are also more vulnerable to surprise; they become implicated spectators instead of direct actors.

"We have a tradition of breaking up interactions by subject matter and by object," London said. "In the core game cycle, you are using the money your Sims made to purchase new objects that improve their lives. This means it's really at the object level that you are giving commands. Having a 'Clean the house' button really doesn't bring home the feeling that there's a new object for your Sim to use, such as the TV."

"That said, some objects have a higher granularity of control than others. You want to feel like you are telling a Sim to do a specific thing, but not so minutely that you are the Sim. For example, you tell a Sim to prepare breakfast by choosing waffles. But you don't actually control their whisking the batter. Neither do you say 'Eat', as that robs the player of the specifics of storytelling, the center of our game. It's a granularity that we're been refining on a case-by-case basis since we started this business."