Hearing, sight, taste, touch and smell: these are the five senses to which we constantly refer when speaking of the human being. But in recent years, many scientists have argued that we would have four others, namely proprioception (knowing where our own members are), equilibrioception (maintain balance) thermoception (feel the temperatures) and nociception (know the pain).
And it would seem that the human resources do not stop there: an English study carried out on blind and sighted participants showed that the human being was able to move around in its environment using only tongue clicks.
Loss of sight, blindness: using sounds to get around
Researchers at Durham University looked at how people can use echolocation to move in space. This type of sonar is used by many animals in nature: bats, shrews, dolphins and other cetaceans emit sounds in their environment in order to locate space and identify obstacles and possible threats.
During 20 training sessions, lasting approximately 2 to 3 hours, volunteers learned to move around without being able to locate themselves by sight. “The training resulted in remarkable behavioral changes for all participants”, noted the authors of the study. And for good reason, in just ten weeks, the 12 blind participants and the 14 other sighted volunteers learned to navigate various mazes with tricky layouts, including corridors with sharp intersections and zigzags. Even better: thanks to the echoes of their tongue clicks, they also understood how to identify the size and orientation of objects and surfaces in their path.
Echolocation to see your environment without your eyes
The researchers noted that echolocation allows human beings to learn to “see” their environment using the visual parts of the brain, without the sense of sight being used. According to them, this skill can be developed into adulthood and even into old age. Indeed, in this experiment, blind people aged up to 79 all succeeded in developing this echolocation skill.
“It is important to note that when we quantified the degree to which participants improved from Session 1 to Session 20 in their abilities for each of the tasks, there was no evidence of an association between age and performance in practical tasks”, said the scientists. Indeed, even though they took longer to exit the maze, older people did not have more collisions than their younger counterparts.
Three months after the end of this training, the blind participants feel a distinct improving their mobility through echolocation. In a follow-up survey, 10 of 12 participants also said that this new skill had benefited their well-being and independence.
“We’re very excited about this,” said psychologist Lore Thaler of Durham University in the UK, reports Science Alert.
“And we think it would make sense to provide information and a click echolocation training for people who may still have good functional vision, but are expected to lose their sight later in life due to progressive degenerative eye disease.”