Research by British scientists reveals that our tactile perception transcends the boundaries of immediate physical contact.
This discovery challenges established conceptions about the limits of our senses, unveiling a human potential shared with certain bird species. The study opens up novel perspectives on how our nervous system interprets mechanical signals propagated in the environment.
The collaborative research conducted by teams from
University College London and
Queen Mary University of London explores this little-known faculty called "remote touch." Unlike vision or hearing which perceive stimuli at a distance, touch was considered necessarily proximal. However, experimentation demonstrates that our hands can detect the presence of concealed objects before any direct contact, thanks to an exceptional sensitivity to micro-displacements of surrounding particles.
The mechanisms of a previously ignored perception
The study relied on a rigorous experimental protocol involving twelve participants. They had to locate a cube buried in sand by making slight finger movements on the sand without establishing physical contact with the cube. The results revealed a detection accuracy reaching 70.7% within the theoretical detection range, proving the reality of this remote perception in humans.
Physical modeling of the phenomenon revealed that human hands perceive the minute mechanical disturbances generated in the granular medium. When sand moves around a buried object, it produces mechanical "reflections" that propagate to the surface. Our sensory system would be capable of interpreting these subtle signals, approaching the theoretical detection limits predicted by physical models.
This ability shows striking similarities with that observed in shorebirds like sandpipers. The latter use their specialized beaks to detect buried prey by interpreting pressure variations in wet sand. The study published in
IEEE International Conference on Development and Learning thus establishes an unexpected bridge between human and avian perception.
Technological applications and perspectives
Comparison with a robotic system equipped with tactile sensors provided valuable insights. The robotic arm, trained by a long-term memory algorithm, could detect objects at slightly greater distances but with significantly lower overall accuracy (40%). This performance difference shows the effectiveness of human sensory processing when faced with ambiguous signals.
The technological implications of this discovery are considerable. As explained by Zhengqi Chen, a PhD student at the Advanced Robotics Laboratory, this new understanding paves the way for assistive tools and technologies that extend human tactile perception. Robotic systems could integrate this natural sensitivity for delicate operations in complex environments.
Archaeological and space domains are among the potential beneficiaries of these advances. The detection of fragile artifacts or the exploration of Martian soils could be improved by systems capable of interpreting very weak mechanical signals.
To go further: What is remote touch in birds?
Some species of shorebirds possess an extraordinary ability to locate their prey buried in sand. Their beaks contain specialized sensory receptors for detecting pressure variations.
Previous research shows that sandpipers use pressure gradients to identify buried crustaceans. Their sensitivity allows them to discriminate prey at several centimeters depth without direct contact.
Habitat structure influences this ability. Seagrass roots can obstruct pressure fields, reducing detection performance. Conversely, sand moisture improves signal transmission.
Article author: Cédric DEPOND