The sense of touch is so important. Probably more important than we even realize. It's one of the senses we don't really think about, until something calls attention to it—like when you cut your thumb and have to wear a band-aid for a few days. Suddenly, you realize how much relies on that one thumb: typing, peeling a banana, unlocking your phone. You'll forget about it for a minute and then suddenly: agh! It's partly why the social isolation of COVID was so traumatic for everyone: no more handshakes, no kisses on the cheek, no hugs.

How Fast is Virtual Movement?

When it comes to touch, the brain does a lot of quiet work to interpret subtle cues and we depend on that feedback constantly, whether we notice it or not. That makes touch especially important in the design of immersive technologies like virtual reality (VR) or augmented reality (AR), where replicating the feel of physical motion and texture can make or break the experience. Until now, however, there's been a gap in how these sensations are replicated. While we've become experts at simulating vibration or pressure, we haven't yet found a way to control how fast virtual movement feels.

We're Working On It

Researchers at NTT Communication Science Laboratories, in collaboration with the University of Electro-Communications in Tokyo, are working on ways to fill this gap. They have discovered that the perceived speed of a virtual object moving across the skin can change, even if its actual speed stays the same.

Tactile Tricks

To be more specific, when a series of tactile points is spaced farther apart, motion feels slower; when the same points are closer together, it feels faster. Until now, we had thought that spacing—a factor usually linked to resolution—had no effect on how speed is felt. As long as the actual speed of the stimulus remained the same, the distance between individual touch points wouldn't matter. Spacing only influenced how detailed a tactile display felt, like the sharpness of an image, but not the perception of motion itself. As a result, designers and researchers focused on force, frequency, or duration when trying to shape how fast something felt. But we were wrong!

All About Spacing

To prove it, our researchers built a specialized haptic interface that can deliver touch sensations over a wide area of the hand, from fingertip to palm, and at a high spatial resolution. The system uses discrete pins to stimulate different points on the skin in sequence, simulating the feeling of an object moving. By adjusting the distance between those stimulation points, they were able to isolate the influence of spacing from other touch-related cues like vibration or skin deformation. They then carried out controlled experiments where participants compared the speed of two virtual motions: one with tightly spaced points and another with wider spacing.

The results? People consistently felt that the widely spaced version was about 25% slower.

Previously, one of the main challenges in studying touch perception was the difficulty of separating the different sensations involved. Past research used physical objects, where cues like vibration, motion, and skin stretch were mixed together. This made it hard to pinpoint what was actually influencing a person's perception. The research team's work solves that issue by isolating one factor: the positional cue created by stimulating separate points in sequence.

Here are four examples of how the research could lead to real-world improvements:

How the Brain Feels Motion

Realism in virtual touch isn't just about adding more force or more vibration. It's also about understanding how the brain interprets patterns of motion on the skin. By finely tuning the details of that motion, such as how far apart each touch is, developers can guide the user's perception in subtle but powerful ways.

As Extended Reality (XR) becomes more a part of our daily life, from entertainment to education to industry, having better tools will make virtual experiences not just believable, but more useful and intuitive. NTT is at the forefront of that virtual revolution.

NTT—Innovating the Future

For further information, please see this link:
https://group.ntt/en/newsrelease/2025/03/19/250319b.html

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Daniel O'Connor

Daniel O'Connor joined the NTT Group in 1999 when he began work as the Public Relations Manager of NTT Europe. While in London, he liaised with the local press, created the company's intranet site, wrote technical copy for industry magazines and managed exhibition stands from initial design to finished displays.

Later seconded to the headquarters of NTT Communications in Tokyo, he contributed to the company's first-ever winning of global telecoms awards and the digitalisation of internal company information exchange.

Since 2015 Daniel has created content for the Group's Global Leadership Institute, the One NTT Network and is currently working with NTT R&D teams to grow public understanding of the cutting-edge research undertaken by the NTT Group.