Touch is the sense we understand the least – but maybe not for much longer

What tells you your bladder is full? Your body uses a sense that is so all-pervasive it’s normally kept at a subconscious level so we aren’t overwhelmed with information. Sometimes referred to as a sixth sense, this internal sensing ability is actually part of the “mechanical sense” that includes touch. It tells you where your legs are and whether they are safely touching the ground; that your shoulders are connected to your arms, and so on.

It relies on a network of nerve endings that constantly monitor our hair, skin, guts, bladder, joints, muscles, arms, legs and blood pressure. Have you ever woken unable to feel your arm? This is because reduced blood supply has sent the nerve endings to “sleep”. You can move it – but you can’t control it. When “feeling” returns, you slowly realise the arm is actually yours again. In rare cases, people can lose the sensation in much of their body permanently.