Since our earliest prehistoric ancestors, touch has been central to our survival and reproduction. Writer and neurobiologist Dr Liam Drew explores how our bodies have evolved to tell us more than we realise.
Touch is our most intimate sense. Sight, smell and hearing evolved to understand the world at a distance, but touch, like taste, analyses objects in direct contact with our body.
What you touch is likely to have a direct bearing on survival or reproduction. It might be predator, prey or parasite; parent, lover or child; shelter or hazard; tool or food; the ground that you walk on or the branch from which you seek to swing. It is also the first sense to develop, with some foetuses responding to touch in the womb after just eight weeks.
You’ve got some nerve(s)
Our bodies are designed to ensure that touch is inherent to everything we do. Regions of our brain and spinal cord are dedicated to processing the information gathered by touch, while the nerves that run through our flesh to the surface, lying just beneath the skin, convert external pressure and energy into a biological signal that signifies a sensation.
Evolution created a touch system composed of different sensors and receptors, which together detect the qualities of what is touching our body and what our body is touching – its weight, temperature and texture – so that we can deduce what we need to know.