In the gentle flow of sand over a fingertip, a quiet surprise emerges—one that invites us to reconsider what it means to touch. Picture your finger gliding slowly across a granular surface, not yet making contact with the object beneath, yet somehow feeling its presence. In that moment, the ordinary notion of tactile sensation stretches into something more: a subtle whisper of mechanical shifts, a faint echo of what lies hidden. This is the stage on which scientists now say we may have discovered a new dimension of touch—a “remote-touch” ability that siblings the sixth sense, and perhaps opens the door to a seventh.
Researchers from Queen Mary University of London and University College London sought to test whether humans could detect objects hidden beneath sand without physically making contact. They drew inspiration from nature — shorebirds such as sandpipers and plovers probe the sand and sense prey through mechanical cues transmitted in the granular medium. The scientists reasoned: could our fingertips, though lacking specialized beaks or sensors, still tap into these faint cues?
In a series of experiments, twelve volunteers aged 18-26 were asked to slide a finger at a consistent pace (about 2 cm/sec) through a box of dry sand. A small cube was buried at an unknown location. The volunteers used only their tactile sense—no visual cues—to stop when they felt something out of the ordinary. On average, participants stopped about 2.7 cm before actual contact, with a hit-rate precision of roughly 70.7 %.
By modeling the physics of granular media, the researchers estimated that mechanical “reflections”—tiny displacements in the sand caused by the buried object—should be detectable up to a theoretical limit of about 6.9 cm under ideal conditions. Humans came close to this bound, suggesting our tactile system may be more capable than previously believed.
Comparatively, a robotic arm equipped with tactile sensors and trained using a long short-term memory (LSTM) algorithm performed the same task. The robot detected the object from slightly farther distances in some trials, but with much lower precision (about 40 %) because of many false positives. Humans still out-performed machines in discerning real cues from noise.
What does this mean for our understanding of perception? Traditionally, touch is conceived as a proximal sense: you must come into contact with something to feel it. This study challenges that boundary by showing that our sense of touch may have a spatial extension through the materials we interact with. As lead researcher Elisabetta Versace puts it: “It changes our conception of the perceptual world (what is called the ‘receptive field’) in living beings, including humans.”
Pragmatically, this ability might have applications: from designing assistive tools for excavation or search-and-rescue operations in granular or low-visibility environments, to inspiring robotic tactile systems that mimic human haptic perception. The interplay between human and robotic experiments in this study underscores how understanding our own sensing capabilities can guide technology—and vice versa.
Yet we should tread with caution. While the evidence is compelling for this particular medium (dry sand) and task (buried cube detection), we do not yet know how far this extends into other materials (mud, wet sand, rubble), other body parts, or more complex objects. Whether it represents a fully new “seventh sense” or simply an extension of our touch system remains open to further investigation.
AI image disclaimer: “Illustrations were produced with AI and serve as conceptual depictions.”
Sources: Sci.News Earth.com EurekAlert! IFLScience NDTV