Our sense of touch is fundamental and often taken for granted. How can we bring greater awareness and appreciation for this important sense?
We start developing a sense of touch before we are born and can distinguish between self-touch and the touch of another when we first enter the world. All animals have evolved with a sense of touch, even single-celled organisms. Many plants can also respond to tactile stimuli. The tactile hair of early mammals that provided a sense of touch evolved before the secondary use of hair as a protective insulator. Seals and walruses have very sensitive whiskers that can sense fish moving in the water in complete darkness. The whole area of touch is one of the least researched and understood of the senses, which includes how the body’s largest sensory organ, the skin, evolved.
Of all the parts of the human body that experience touch, it’s the fingertips of our hands that evolved to be the most important. In a recent study, scientists found that people can detect nanoscale (one-thousandth of a micrometre) wrinkles on a smooth surface with their fingertips. Although receptors on the skin are fundamental, other senses contribute to our sense of touch as we experience the world around us. For instance, as we pick up a glass of water to drink, we move our hand in space, grip the glass, sense the weight, and move the glass to keep the water level. This apparently simple movement involves the coordination of multiple senses like vision, tactile sensations and haptic feedback, and proprioception, the sense of where our body is at any given moment.