Run your fingers lightly over the image of a spiny, striated fossil on one of Disney’s new “textured” touchscreens and your nerve endings will lie to your brain. That’s no mere flat picture, say the signals coming from your fingers, it’s a bumpy object pressing out of the screen like one of those faces pushed through a sheet in a horror flick.

Disney — yes, that Disney, of Walt and Mickey and Donald fame — says it’s thanks to a haptic feedback algorithm created in one of its Disney Research labs that allows you to feel textures across an otherwise smooth surface. The algorithm works by deploying subtle vibrations through a special electro-vibration-based display that tricks fingers (or really, the brain) into thinking there’s dimensionality to the object beneath the surface. As your fingers skate across the level image, those vibrations allow you to explore the image’s simulated bumps and ridges.

Slide your finger over an actual ridge on a real object and your finger and brain can articulate its dimensionality because of the way the skin stretches and constricts as it moves. Disney’s algorithm uses nuanced vibratory feedback to simulate that stretching, thus while whatever image or video is still just pixels lit beneath a translucent screen, what you’re feeling is for all intents and purposes real.

“Our brain perceives the 3D bump on a surface mostly from information that it receives via skin stretching,” said Ivan Poupyrev, who runs Disney Research’s interaction group in Pittsburgh, in a company press release (PDF). “Therefore, if we can artificially stretch skin on a finger as it slides on the touch screen, the brain will be fooled into thinking an actual physical bump is on a touch screen even though the touch surface is completely smooth.”

Here’s Disney’s video overview:

[youtube=http://www.youtube.com/watch?&v=zo1n5CyCKr0]

By creating what it calls a psychophysical model (a kind of map of haptic sensation), Disney says it’s been able to index the vibration-creating voltage to the perceived frictional force, giving its algorithm sufficient granularity to “generate any desired frictional force between the user’s finger and the surface.” From video to pictures to topographical maps (think depth and elevation), Disney claims it can simulate virtually any combination of ridges, edges, protrusions and bumps.

I’m reminded of one of my 14-month-old son’s favorite books, Touch & Feel Farm. “Touch the cow, do it now,” commands the author beside a flat drawing of what looks like a Jersey Heifer, one of the spots a velvet swathe of brown. My son will sit for minutes on end flipping through the thing, touching the cow, patting the pig (pink suede!), feeling the ground (sandpaper) and so forth. With Disney’s technology, you could have that book up on a tablet or smartphone in no time, probably offering even more texturing options, since you’d be free of economic publishing strictures.

Let’s not forget Disney’s hardly alone in pursuing this technology: Rumors of a haptic iPhone or iPad touchscreen keyboard that uses voltage to simulate the sensation of touching physical keys have been circulating for years, and last February, an Apple patent emerged for a vibratory haptic interface.

Tactile Rendering of 3D Features on Touch Surfaces [Disney Research]