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Excerpted from How to Feel: The Science and Meaning of Touch by Sushma Subramanian. Copyright © 2021 Sushma Subramanian. Used by arrangement with the publisher. All rights reserved.
“Think about televisions and computer displays for your eyes, and speakers for your ears,” Ed Colgate, a professor of mechanical engineering at Northwestern, tells me at the annual World Haptics Conference being held at his university. “Haptic interfaces are the same thing for your hands. Haptic engineers develop devices that can be programmed to feel and behave like all manner of things when you touch ad interact with them.”
Colgate is a well-loved, avuncular leader in the field of haptic engineering. He led the first-ever World Haptics Symposium, which became part of the World Haptics Conference, and was the founding editor in chief of the leading journal on the subject, IEEE Transactions on Haptics. He explains that the small feelings like rumbling, skin pressure, and muscle strain give us cues about whether we’re handling our technology—hammers, cars, you name it—correctly. These signals are missing in many of our virtual interfaces, like when we’re using a controller to moderate the speed of a car in a video game or remotely operating a robot. This places a heavier burden on us to concentrate with our eyes. That’s why engineers working in haptics are working on finding ways to reproduce the most useful of these sensations.
Colgate and I are in a large hall trying out tactile novelties. There are phones that let a user send a vibrational pattern, like the beating of a heart, to someone on the other end of the line. There’s a dental training simulation that quite convincingly imitates the way it feels to drill into a tooth. Several other presenters are unveiling not fully developed applications but small haptic tricks that they hope to implement one day. One has as stationary block that, when vibrated in a particular pattern, gives the impression it’s going from sticky to smooth even though the surface isn’t changing at all. Another presenter has me try on a belt that vibrates at my side and makes me reflexively turn at the waist.
The poster boards have titles such as “Active Touch Perception Produced by Airborne Ultrasonic Haptic Hologram,” “Should Haptic Texture Vibrations Respond to User Force and Speed?,” “The Effect of Manipulator Gripper Stiffness on Teleoperated Task Performance,” and “The Effect of Damping on the Perception of Hardness.”
The field of haptic engineering originated in the 1940s, but it remained a small and mostly ignored subspeciality of engineering until a few years ago, when Apple introduced “force touch” to its MacBook laptops and the word haptics finally went mainstream. There are sensors in the trackpad that detect how much pressure is being applied, and when they detect the downward force, a motor pushes the trackpad against the finger and vibrates slightly to simulate a click. The finger feels like it is moving down and back up, but it’s not. The pad is also responsive to different kinds of touch. Depending on the number of fingers that are used and how they move, we can change the size of the screen, scroll, and toggle between displays.
This development—using our fingers in multiple ways to interact with a trackpad and with our screens—has opened up possibilities for the field because it required entirely new ways of thinking about how a user could use touch. Engineers are developing a new tactile language that mimics the kinds of maneuvers we make with three-dimensional objects, such as the shuffling of images or the flipping of pages on a flat surface. The challenging part is to make us feel them. Haptic engineers believe these tactile cues matter much more than we realize. They lament the loss the tangible interaction that we used to get when our devices had levers, switches, and gauges, and they’re hoping they can bring them back.
While our technology is presented to us as ever improving, a generation that grew up with digital tools is now seeing renewed value in analog. The reason we continue to prefer some of our older artifacts isn’t just about nostalgia or street cred. We’re gravitating toward touch. We may not be aware of all the tickles and bumps we get from physically handling objects, but in subtle yet significant ways they affect how we think. They activate parts of our minds associated with action and get us to engage with them in a different and deeper way. Adding more tactile effects to our phones and computers could do the same. They can make us feel more connected to our devices and trigger us to manipulate and play around with them in new ways, perhaps even expanding the possibilities of what we can create with them.
This is what’s on my mind over the months following the World Haptics Conference. But it’s not what I’m thinking about when I finally get a pair of Tpads, special touch-enabled tablets, mailed to me at my new home in Fredericksburg, Virginia. In the past few weeks, my life has been a whirlwind. I’ve moved here for a job teaching journalism at a university south of Washington. Getting the job offer set off another course of events in my romantic life. My boyfriend, Kartik, had supported my taking the position, but as my move came closer, it was clear he was having doubts about joining me. He was worried about what it would mean for his own career, but we didn’t talk about it that much. Instead, we got into many passive-aggressive fights. After one of these, we broke up. Then, a couple of days before I left, we decided to change course and get engaged instead.
As I’m sitting alone in my stark new faculty apartment, surrounded by the standard-issue dorm furniture, I obsess over everything that’s happened between us. I wonder if we made our decision too fast and whether Kartik felt forced. Maybe it was all a huge mistake. But I don’t tell him any of this. Instead, we talk about how much I’m enjoying getting to know my colleagues and students and about the Pinterest pages I’ve been checking out for inspiration for our wedding. We’ve never been good at heartfelt conversations over the phone. With the Tpads in hand, I’m excited to have a project to work on with him, something to get our minds off of everything that’s happened between us. And I’m not just interested in solving engineering questions anymore; I want to know how communicating through touch could help bridge the distance between us.
On my next weekend trip up to New York to visit Kartik, I give him one of the Tpads and tell him that we’ll be performing an experiment together. By sending haptic messages to each other for a few days, he can help me figure out what touch might contribute to our technology. There’s a program on the phones that lets us send haptic pictures. It turns the black-and-white images we take into a textural pattern based on their lightness or darkness. The first week I get some images of the wood grains on his desk and the creases of his hand. They’re kind of interesting to feel. His favorite of mine is a picture of my pajamas, which are covered in black-and-white snowflakes. The stark pattern creates a texture on the screen that is almost like softness when he touches it.
“Do you think touching them helped you feel closer to me?” I ask.
“Well, the pajamas reminded me of you,” Kartik says. “I don’t really think it was the haptics.”
I don’t think the images are very compelling, either. The experiment fizzles out when we stop taking our phones out with us because they’re bulky and we’re hardly sending each other anything anyway. I’m disappointed, and I end up talking over the issue with my new colleague, a computer science professor. Together we come up with a new plan. What would be even better than the static haptic pictures would be the ability to touch Kartik virtually in real time. My colleague says he can have his son, a computer scientist based in Austin, Texas, whose hobby is creating prototypes for smartphone apps, make an app for us. He has it ready a week later, and we agree to test it out together at first.
When I swipe over the image of a finger on the display, it feels as if my colleague touching me back. His finger doesn’t have the texture of a real one, but it does seem ever so slightly raised, like he’s reaching out at me. I keep running over it, amused, because I can see with my own eyes that the glass is completely flat. The vibration of the screen’s surface is changing imperceptibly depending on where my skin makes contact with it. My brain interprets this tiny shift in friction as a three-dimensional bump. It takes me a few seconds, as I move my finger back and forth, to remember that I’m having this exchange with an actual human, and I stop abruptly. I wonder if he’s as creeped out as I am.
I’m as uncomfortable as I would be if I were fondling a real stranger in the flesh. I don’t know him well enough to ask if he feels the same way, but the stiltedness of his speech and the speed with which the image of his finger disappears when I’m done suggest that what he’s experiencing is not too dissimilar from me. I thank him profusely and get off the phone quickly. I actually take our mutual aversion as a good sign. If this short interaction could elicit the same kinds of emotions as true skin-to-skin contact with someone we don’t know, then I’m hopeful that the same might be true when I use it with Kartik.
Kartik gets the phone in the mail soon after, and we test it together. Our fingers meet up near the center of the screen, and I can feel the little raised spot, like the glass screen is a little warped. We stay there, rubbing the impression of each other’s presence. I let him take a few seconds to make sense of what he’s feeling and then I move my finger away. He tries to come closer again. I dart away, and he chases me. I stop and let him catch me, letting his finger linger on top of mine. We gently nuzzle them against each other. We are flirting, haptically!
OK, it doesn’t feel anything like the intimacy of skin-to-skin contact, but it is surprisingly moving. For the first time in a very long time, we’re allowing ourselves to connect. Instead of being burdened by hashing out what’s happened over the past few months, we’re enjoying each other’s company the way we did when we had just started dating. We realize we need more moments like this one. When our emotions are at their most intense and the words haven’t been coming, it is through touch that we are able to express ourselves again.
Soon after our experiment, we have to give our phones back to the lab, and I miss them immediately. It’s akin to someone telling me that I can keep my smartphone, but it won’t have a camera or a voice recorder anymore. Having that extra ability opened me up to new ideas about what my technology can do for me. What I had once thought of as a needless accessory had become an essential communication tool. That’s what so often happens with our gadgets. We don’t realize we need something until we have to give it up.