The epic battle between video game consoles seems to have a clear winner: the Nintendo Wii.

The Wii, which uses an innovative wireless controller to translate the players’ motions onto the screen, has upset the order of the video game world. In electronics stores and elsewhere, there are growing signs that the Wii has taken the lead in buzz and sales over another new console, the Sony PlayStation 3, which offers new superlatives in processing power and graphics.

The competitive picture became clearer on Tuesday, when Sony reported disappointing profits that industry analysts attributed largely to the expensive and shaky rollout of the PlayStation 3 and lukewarm demand for the complex machines. By contrast, Nintendo said last week that its own third-quarter sales were up 40 percent from a year earlier, buoyed by Wii sales.

Why is the Wii so popular? Here’s what consumers have to say:

“You’re up and you’re moving, and it makes you feel more involved,” said Tracy Ciardiello, 28, a stay-at-home mother in Berkeley Springs, W. Va., who bought one of the last Wiis available at a Wal-Mart nearby on Sunday morning.

As I argued a few months ago in Seed, that feeling of being involved in the game has a neurological explanation.

While Nintendo argues that the wireless controller makes game play more intuitive–you no longer have to remember arcane sequences of buttons–it actually does something much more powerful: By involving your body in the on-screen action, the Wii makes video games more emotional.

To understand how the Wii turns Zelda into a passionate experience, we have to revisit an old theory of emotion, first proposed by the great American psychologist and philosopher William James. In his 1884 article “What is an emotion?” James argued that all of our mental feelings actually begin in the body. Although our emotions feel ephemeral, they are rooted in the movements of our muscles and the palpitations of our flesh. Typical of his work, James’ evidence consisted of vivid examples stolen straight from real life, such as a person encountering a bear in the woods.

“What kind of an emotion of fear would be left,” James wondered, “if the feeling of quickened heart beats nor of shallow breathing, neither of trembling lips nor of weakened limbs, neither of goose bumps nor of visceral stirrings, were present?” James’ answer was simple: without the body there would be no fear, for an emotion begins as the perception of a bodily change. When it comes to the drama of feelings, our flesh is the stage.

The Wii is vivid proof that William James (and, by extension, Antonio Damasio) are right: our emotions begin in the body. Unlike other game consoles, which leave us stranded on the couch, the Wii actually makes us move. If we want to win the boxing match, or defeat the evil monster trying to devour Super Mario, then we need to stab and parry and prance, not just twiddle our thumbs. We might look a little foolish, but the game has managed to excite our flesh, and that means our emotions aren’t far behind.

Can you think of any other applications for this research? I’d often thought that roller coasters would be much scarier if they got our pulse rising and adrenaline pumping before the ride began. Perhaps amusement parks should make us run a lap or two prior to getting on the coaster.

And it’s also worth noting that music is such an necessary part of movies precisely because it triggers changes in our body. When listening to music, the pupils in our eyes dilate, our pulse and blood pressure rise, the electrical conductance of our skin is lowered, and the cerebellum, a brain region associated with bodily movement, becomes unusually active. Blood is even re-directed to the muscles in our legs. (As a result, we begin tapping our feet in time with the beat.) All these bodily changes make our mind more primed for emotion; Jaws isn’t nearly as scary without that throbbing double bass preceding the appearance of the shark. The music excites our flesh which triggers our fear. As Schopenhauer wrote, “It is we ourselves who are tortured by the strings.”