Is the laundry still damp, or just cold? Why your skin can’t tell the difference

Roger Diaz Gomez/Getty Images It’s a cold winter afternoon and you’ve just brought the washing in.

Suddenly, you pause.

Are these clothes a bit damp? In the laundry basket, your hand can clearly distinguish the textures of silky shirts, woollen jumpers, cotton bed sheets.

So why is it so hard to tell whether the washing is cold and damp, or just cold? A sensible guess might be that our hands are numb from the cold, making it harder to detect wetness.

The less intuitive reality is that we humans completely lack any specialised sensors that respond to “wetness” in the first place.

That’s right – your skin alone can’t actually detect if something is damp.

How do we tell if something is wet? Our ability to sense information about our external environment starts at nerve cell endings in our skin.

There are specialised molecules on the surface of these nerve cells called sensory receptors.

They convert environmental information into a biological signal, which is amplified into an electrical impulse and transmitted along nerve cells to the brain.

There are numerous different sensory receptors in nerve cells that are activated by cold, warmth or damaging heat.

There are also sensory receptors that respond to very precise tactile information such as vibration, friction or stretch.

When you put your hand in that laundry basket, all the information about temperature and texture comes from the relevant sensory receptors in your hand.

The electrical signals triggered by these multiple inputs can also be integrated together in the central nervous system, or the brain.

In this way, we can infer an extraordinarily nuanced sense of our environment.