Skin is a material with astonishing capabilities: the flexible, waterproof layer constantly regenerates itself, heals itself after scratches and cuts, and, through its nerves, conducts electricity, relaying the sense of touch to the brain. Engineers have long been trying to come up with a synthetic polymer that does all those things, and does them under standard conditions rather than the carefully calibrated set-up of a lab. Now engineers have created a polymer with a combination of skin’s most elusive attributes that no polymer had achieved before: This new material, reported in Nature Nanotechnology, can conduct electricity and, when it is sliced open with a razor, can heal itself at room temperature.
Are your fingers resting on a slick touchscreen or a wooden desk? The sense of touch and ability to differentiate between textures provide invaluable information about the world around us—and now they may be able to transmit that information to robots and prosthetic hands at well.
Researchers have developed a mechanical “finger” called the BioTac, made up of a rigid central sensor surrounded by liquid and covered in a flexible skin. When the BioTac strokes a surface, that surface’s texture produces unique vibrations in the skin, which has ridges like those seen in a human fingerprint. And the BioTac’s software can interpret those vibrations, along with the force that the surface exerts on the mechanical finger, to identify 117 different textures with a 95 percent success rate. In fact, when it came to distinguishing between textures, the BioTac actually out-performed humans.
[via Pop Sci]
Video courtesy of University of Southern California
What’s the News: Georgia Tech researchers have now created a glove that heightens your sense of touch. Presented in May at the IEEE International Conference on Robotics and Automation, the glove—which applies high-frequency vibrations to the side of an exposed fingertip—can improve a wearer’s motor skills and tactile sensitivity. “This device may one day be used to assist individuals whose jobs require high-precision manual dexterity or those with medical conditions that reduce their sense of touch,” Georgia Tech assistant professor Jun Ueda said in a prepared statement.
The simple act of picking something up requires a plethora of decisions: Is the thing light or heavy? How much force do I need to grip it? If I grip too hard, will I crush it with the might of my mighty hands?
As we grow up we become fairly practiced at the art of picking up (objects, that is), so our brains will do most of this for us without a lot of conscious thought. But all those variables—plus adapting to a surprise on the fly—mean that picking things up with the proper force is one of the most difficult skills to teach a robot. That’s why the design by Eric Brown’s team is so clever.
In this week’s Proceedings of the National Academy of Sciences, Brown and colleagues demonstrate (paper in press) their “universal gripper,” a successful prototype of a robot hand. It’s based on an idea that’s been around for a while, and it looks like a beanbag on a robot arm, because, well, that’s kind of what it is.
Touch comes first. It’s the first way that people interact with the world, MIT’s Josh Ackerman says, and touch can change the way you feel about the world or engage with it.
Ackerman and colleagues published a study in Science this week further uncovering the ways that what we touch influences what we think. In a series of experiments, his team demonstrated numerous examples of the tactile altering the mental, like people negotiating more stubbornly when sitting in hard, uncomfortable chairs, or taking decisions more seriously when holding a weighty object like a clipboard.
The idea, then, is that due to the strong connection between our senses and our thoughts, touching a surface can trigger feelings related to the metaphorical value we assign to it. Or, more simply, the feeling of weight makes us feel like a decision is more “weighty,” a harsh surface like sandpaper leads to harsh feelings toward other people, and the touch of smoothness makes us feel like things are going to smooth over.
“The tactile sensation is extremely important early in development. The idea that other associations would be built on that makes intuitive sense,” said Franklin & Marshall College psychologist Michael Anderson, who was not involved in the study. “Brain regions that may initially have been dedicated to one particular task, turn out to contribute to multiple tasks” [Wired.com].
For more on this, check out Ed Yong’s in-depth post at Not Exactly Rocket Science.
Not Exactly Rocket Science: Heavy, Rough, and Hard: How Things We Touch Affect Our Judgment And Decisions
80beats: In a Sensory Hack, What You Touch Affects What You See
80beats: Fingerprints Are Tuned to Amplify Vibrations and Send Info to the Brain
80beats: Warm Hands Give People a Friendly, Generous Outlook
80beats: Hand Washing After a Decision Scrubs Away Those Lingering Doubts
What are fingerprints good for, besides aiding police investigations? That’s the question that biomechanics researcher Roland Ennos recently set out to answer. This notion that human fingerprints (and presumably footprints) evolved because they act like tire or boot tread–increasing the friction against a smooth surface so we don’t slip or drop stuff–is a 100-year-old urban myth that, apparently, had never been put to the test [NPR].
To test the impact of fingerprints, Ennos rigged a machine that measured the amount of friction generated by a fingertip (belonging to study coauthor Peter Warman) when it was pressed against a piece of acrylic glass. Warman gradually increased the pressure, going from a light touch on the glass to a tight grip, but the corresponding friction didn’t increase as much as the researchers expected. Soon they realised that the skin was not behaving like a normal solid, where friction is proportional to the strength of the contact. Instead, it was behaving like rubber, where the friction is proportional to the contact area between the two surfaces [BBC News].
Specialized cells found only on flower petals have the same basic function as nonslip mats that prevent people from slipping in the shower, a new study has determined. The bumpy cells, called conical cells, help bees come in for a landing on the flower petals and find their footing, so they can get down to the important business of pollination.
Conical cells had been something of a botanical mystery, with most researchers assuming they played a visual role. One hypothesis held that by modifying the spectral properties of the petal, the cells enabled the plant to appear brighter to pollinators [The Scientist]. In the study, will be published in a forthcoming issue of Current Biology, researchers showed that the conical cells’ main function is to provide friction, and that bees can detect them by touch. The first experiment used two kinds white snapdragons that looked identical to both human and bee eyes, but one was a mutant with flat cells instead of conical. The bees initially went to both flower types, but after 20 visits they chose the blossoms with conical cells more than 80 percent of the time.
Scientists have found that manipulating a person’s sense of touch can confuse their sense of sight, an intriguing finding that suggests that touch and vision are integrated in the human brain…. For decades, instructors in medical schools have taught students that the senses —including vision, touch and sound — are interpreted in different, discrete parts of the brain, says Michael Beauchamp of the University of Texas Medical School at Houston. “Now it turns out what we’re teaching them is wrong,” he says. “There’s a lot more cross talk between the modalities” [Science News].
In the experiment, which will be published in an upcoming Current Biology, researchers used a postage stamp-sized device that used tiny pins to stroke the test subject’s finger in either an upward or downward direction. When subjects watched a stationary stripe on a computer screen after a machine stroked their fingertips, the motion of the stroking created the illusion that the stripe was moving [ScienceNOW Daily News].
Everyone knows that scratching relieves an itch–but how? Neuroscientists now say they’ve found part of the answer in a new study of macaque monkeys. Previous research has suggested that a specific part of the spinal cord – the spinothalamic tract – plays a key role. Nerve cells in this area have been shown to be more active when itchy substances are applied to the skin. The latest work … found that scratching the skin blocks activity of nerve cells in the spinothalamic tract during itchiness – preventing the spinal cord from transmitting signals from the scratched area of skin to the brain [BBC News].
The findings could eventually lead to medical treatments for humans, says lead researcher Glenn Giesler. More than 50 conditions can cause serious itching, including AIDS, Hodgkin’s disease and the side effects of chronic pain treatment…. Some terminal cancer patients even cut back on pain medication just to reduce the itch, he said. Scratching can lead to serious skin damage and infections in people with chronic itch, he said. So scientists want to find ways for such people to relieve their distress “without tearing up their skin,” he said [AP].