Chances are that you haven't really considered putting biofeedback in your games. And why would you? There's no mainstream market for biofeedback-driven video games, and the technology is still niche. But just because biofeedback in games is niche now doesn't mean it won't gain traction as the march of technology moves onward. As part of Gamasutra's Advanced I/O Week, I spoke with a couple of the most notable people in the field of biofeedback in games, to get their take on whether it's a space worth exploring.

Lat Ware, Throw Trucks With Your Mind

Lat Ware is the developer behind Throw Trucks With Your Mind -- a first-person puzzler in which players must use a combination of concentration and mental relaxation to pick up objects, and lob them at enemies, obstacles and other players. I ask him whether biofeedback is really a viable control option for today's game developer. "Well, I wouldn't have quit my job to work on Throw Trucks With Your Mind full-time if I didn't think it was going to be the next Guitar Hero," he answers. "I see biofeedback as the next level of immersion in games," he adds. "The strength of Throw Trucks With Your Mind is that you are actually having a battle of wills with other people over the internet, instead of having a battle of twitch reflexes. It's much more viscerally satisfying to know that you won because you had better control of your brain, not better reflexes." Biofeedback in games allows people to play out their fantasies of altering the world through sheer force of will, he says, and there are a huge number of different ways that biofeedback can be implemented for fun. Plus, the cost of biofeedback in games is coming down. When it releases, Throw Trucks With Your Mind will cost $99 for the game and headset, making it potentially viable for the average consumer -- and Ware has no doubt that electroencephalography devices (EEGs) will be a mainstream input devices within the next 15 years. "I'm just trying to make that happen in 2014," he laughs. "Believe it or not, right now it's possible to do a purely brain-controlled interface for a game for less than $250." "We're in the early stages of the technology becoming affordable," he continues. "EEGs are actually nearly over a century old, and while revolutionary work is being done (like reconstituting images from brainwaves), there is a tremendous amount that is already clinically proven. There are a couple of companies that are capable of the production demands for large-scale EEG games. Right now, the markets are small, made up mostly of the super-early adopters. But one big hit would change that." There are, however, a number of caveats to this technology, such as requiring contact gel - plus, it can take up to a month of training for combat-proficiency, Ware notes. That's why Ware decided to use the EEG tech as a peripheral, rather than the game's primary input device. "We kept standard first-person shooter controls, but took out the guns and added telekinetic powers, and used your brainwaves to control the strength of those telekinetic powers," he says.

"I think that EEGs will be mainstream input devices in the next 15 years. I'm just trying to make that happen in 2014."

For those studios considering biofeedback for their games, what does Ware believe are the best practices for approaching the job at hand? "I talk mostly about EEGs in terms of biofeedback, which is a subset," he tells me. "Other options include muscle tension, heart rate, galvanic skin response, and breath meters, which I am not using." "The best practice in making biofeedback games is also the best practice for game development in general: Make it fun," he adds. "Fun is the only thing that matters in a game. Fun is what makes people love your game. Fun is what makes people come back to play again. Fun is what makes people buy your next game without asking questions." The best way to determine whether your biofeedback idea is fun is to rapidly prototype it and give it to players -- again, as is the case for game development in general. This connection also applies to dodging the worst practices in biofeedback development. "I once worked at a game company where the design team had a clear vision of how the game was meant to be played," Ware explains. "When they saw people playing the game differently, they responded with, 'No, that's wrong,' and nerfed those aspects of the game until it was no longer viable. "The end result was that the gameplay, which was focused around the multiplayer, was completely homogenized with no variation," he continues. "That clear vision made the game very boring. This is, I feel, one of the worst ways you can go about building a game: Forcing the player to play the way you want them to play instead of letting them play how they want. Obviously, you can't incorporate every single play style into every game, but player creativity should usually be nourished." And adding biofeedback features just for the sake of it is also a big no-no, Ware warns. Studios should ask themselves of biofeedback, "How does this contribute to the gameplay?" If it doesn't, it simply does not belong in the game. And Ware believes that, for the most part, biofeedback added into a game as a side-feature, rather than the main course, will typically yield little benefit for the player. "If it was worth putting in the game, it would be worth putting into the core gameplay and making the peripheral mandatory," he says. "If it isn't, then it's not worth being a side-feature. If the biofeedback is a side-feature, you're looking at considerable additional expense to the player for a relatively small part of the game, so the dollars to hours of entertainment ratio is going to be poor. On top of that, if it's not a core feature, then the player will not have had much time to master the skill."

Joseph Gonzalez-Heydrich, RAGE-Control

Joseph Gonzalez-Heydrich is the chief of the Psychopharmacology Program at the Children's Hospital Boston at Harvard University. He's also one of the minds behind the RAGE-Control game system, a game technology that teaches participants to simultaneously calm their emotions, while also engaging their attention to perform tasks in game form. While biofeedback tech is currently possible in video games, Gonzalez-Heydrich believes it will greatly expand in the future. "On the one hand, there's using current available technology to access our physical and psychological states," he explains. "We use one form in our RAGE-Control games. But in the future, I think that technology will improve, and we'll have a greater ability to more accurately distinguish different emotional states, and have those be part of what drives the gameplay, as it is in life." This is the core reasoning behind why Gonzalez-Heydrich believes biofeedback in games will become prominent -- "the games are intriguing to us because they capture, in a more compact and intense way, some of the same struggles and issues that we deal with in life, and that's part of what makes it interesting. As a technology, it allows us to more precisely distinguish different emotional and physical states, then games will become even more interesting." While multi-user biofeedback games are definitely feasible right now with the current tech, it's the development of the preciseness of the tech to distinguish emotional and physical states that will really help the space explode. The RAGE-Control inventor is very keen to stress that, for those studios planning on exploring biofeedback in their games at this early stage, it's never a good idea to claim that your game is capable of something that it's not. "I think that the most important thing is to be scientifically rigorous, and not make claims [about your game] that will only give these sorts of games a bad reputation," he clarifies. "There's evolving brain science behind biofeedback, how our brains react to the world, and bringing that knowledge into game development is very important, otherwise you end up with a fiasco." Fully understanding the science behind biofeedback tech, and letting that inform how players interact with games, is crucial to ensuring the effectiveness of biofeedback-driven gameplay mechanics, Gonzalez-Heydrich says. "Whether that's effective in terms of people just having fun, or if someone tries to create some beneficial change, I think it's important that you test your ideas to see that they really are doing what you think they are doing," he says. "It's the twin pillars of really thinking about brain and psychology in terms of developing a game, and then, however careful you were in devising your game, if you're going to make claims about its effects, I think it's important to test these rigorously to make sure it does that you say it does. The truth will come out." Determining whether biofeedback is adding anything valuable to your game experience is a case of deciding whether you're managing to accomplish the core idea that you set out to achieve. "You want to have an idea of what it is that will drive your players to want to play the game," he adds. "In our case, we had a therapeutic effect, so we thought carefully about how we would do that, and feedback became one avenue into that. I think you go from the beginning of being very thoughtful about what it is that will keep people playing the game." So -- does biofeedback have a genuine future in video games, then? Gonzalez-Heydrich certainly believes this will be the case. "I do think so," he says. "Games are an intense morsel of life, and what makes it exciting to be alive. The more than we're able to put ourselves into the game, the more intense that taste of life is going to be. If you intrigue people, they are going to want to do it."