This is an astonishing ability that certain wild animals possess. Echolocation, or echolocation, consists of putting sounds (often ultrasound, that is to say sounds inaudible to the human ear) and listen to the echo that returns when they encounter an obstacle. Bats, for example, use it to navigate in complete darkness, hunt or to spot obstacles during flight. Dolphins and whales emit clicks that allow them to detect fish and other marine animals, even in murky waters.
Certain human beings, particularly blind or visually impaired people, have developed a form of echolocation naturally allowing them to move around thanks to the sounds produced by their footsteps or by the objects they encounter. A form of superpower? Not so much, if we are to believe this study carried out by the University of Durham, which demonstrated that in ten weeks of training, the human brain can develop this ability to “ see with your ears “.
A structured and accessible learning protocol
Neuroscientist Lore Thaler and her team led this research in collaboration with 26 participants, including 12 blind and 14 sighted. These were subjected to a two- to three-hour twice-weekly training program. The researchers first taught the participants to produce clicks with their tongue, before confronting them with three types of exercises.
The first two aimed to identify the size and orientation of objects, while the third immersed them in virtual mazes where they had to move around using simulated echo sounds corresponding to their positions. For Thaler, the experiment was intended to prove that the scientific community haswas perhaps on the wrong track regarding this faculty of echolocation. “ It has long been thought that the brains of blind people function differently, that it is necessary to lose their sight for this neuroplasticity to develop. “, she explains.
When the brain disrupts sensory boundaries
The results of brain scans taken before and after the training protocol revealed unexpected transformations. Both groups demonstrated an increase in activation of the auditory cortex and a densification of gray matter in the hearing areas after 10 weeks.
Another surprising fact was that the visual cortex of the participants, whether they were sighted or not, began to react to the sound echoes. Evidence that participants’ brains developed a new way of interpreting sounds by mobilizing regions normally dedicated to sight.
This discovery challenges the idea that primary sensory regions are exclusively dedicated to a specific sense, as Thaler explains. According to the scientist, this brain area, the visual cortex, is not simply content to process visual data. She could also integrate information from different senses to improve our proprioception. That is to say our disposition to locate ourselves in space and to be aware of our body; a form of internal GPS of sorts.
Concrete benefits for autonomy
The team also conducted a post-workout follow-up survey. Three months after this, 83% of blind participants reported a marked improvement in their independence and well-being. For Santani Teng, psychologist at the Smith-Kettlewell Eye Research Institute in San Francisco, this feedback is very encouraging. “ This study confirms that this ability, often considered exceptional, is in reality accessible and can be developed through training, whether one is sighted or blind. “.
Faced with these promising results, the research team is currently working to disseminate this training program more widely. For Thaler, echolocation is A ” powerful sensory tool for visually impaired people “. This would therefore be accessible to everyone, thanks to appropriate training. It is possible to draw two other additional lessons from this research. The first is that our brain is much more malleable than we thought ; it is capable of reorganizing itself and creating new neuronal connections throughout life, even into adulthood. The second, perhaps more important, is that the different areas of our organ do not function in isolation, since they are apparently able to communicate and collaborate to process sensory information more efficiently. From a neuroscience point of view, this is a real paradigm shift.
- A study has proven that echolocation can be learned in 10 weeks, by both sighted and blind people.
- The results show that the brain can mobilize the visual cortex to interpret sounds, thus breaking down the idea of brain regions strictly dedicated to certain senses.
- This ability ultimately improves the independence of blind people and also demonstrates the great flexibility of our cerebral organ.