Many actions of magic, and even religious ritual, are fairly described as gestures.
Back when the explanation for why anything beyond the power of man happened was invariably supernatural, man tried to exercise dominion over reality by appealing to the same supernatural, invoking it to do his bidding through finger movements.
Magic was an attempt to cause action at a distance -- to affect things that were far away, for good or ill.
Despite the fact that understanding this is impossible is one of the first things we learn -- at 18 months babies begin to assume that object A cannot be moved by object B unless they touch -- it's still a habit we retain. Who hasn't slammed his or her foot down as a passenger in a car when the driver is going too fast for comfort?
We move to impact the world around us, which is why gestures are the future of human computer interaction.
Whilst the advent of multi-touch screens, and the iPhone that the technology spawned, triggered an explosion of interest in, and in some cases litigation concerning, touch-based interactions, it was Playstation's Eyetoy, a webcam peripheral launched four years earlier, that may have first hinted at what the interfaces of the future might be like.
Xbox's Project Natal is the updated champion of gestural gaming, using much the same framework: a camera tracks the movements of your body and then turns that into instructions for the games.
Removing the physical devices from interaction is, of course, the hallmark of gestural user interfaces.
Detecting contrasts via a camera input is what lets Fluidtunes users scroll through their iTunes tracks by waving their hands in front of the laptops, and what drives responsive projections as you walk by at the airport. Beyond gaming, gestural interfaces are being developed to interact with less, well, interactive devices, especially televisions. According to Paul Lao, the chief technology officer of Panasonic North America, "Gesture control is going to be the next big thing in TV remote control."
The ideal interface is one that doesn't seem like an interface at all. This is a property known as affordance -- the design of the interface indicates how it is to be used. A couch affords the possibility of sitting on it and gestural interfaces need to be as intuitive.
Concepts like SixthSense from MIT's Media Lab and Skinput from Carnegie Mellon and Microsoft Research take gestures back into physical interactions, appropriating the human body as an input device by projecting an interface onto your own body, turning your hand or forearm into a keypad, using affordances developed from using the Windows metaphor.
But pure gestural UIs need to be designed to scream their affordances. They have to explain what they are for and how they are used without saying anything at all. They have to design an experience around a person. Increasingly, the grammar of gestural interface will begin to leak out into expectations from all kinds of experiences, especially those being crafted by brands for a participatory consumer.
For this consumer, everything is interactive.
If the first era of the Web consisted primarily of the transposition of other media formats to it and the 2.0 era reflected the fact that everything should be considered a cultural collaboration of sorts, then perhaps the third iteration is when we take the things the Web has taught us about how people consume and create ideas and export them back to other media, back into the world.
As advertising continues to blur with technology and consumers continue to wrestle back control of their media experiences, understanding how to build those experiences around people so that they intuitively interact with them and enjoy doing so will be a vital skill for brands that want to earn the right to have a role in peoples' lives.
And when you can summon and dismiss a show, or piece of information, or offer, or brand experience, with a flick of your fingers, it will feel a lot like magic.