Why do you laugh your socks off when someone tickles your feet, or burst out laughing when your waist or underarms are tickled?

It’s all in the science.

While science can’t completely explain our uncontrollable giggling when tickled, a report by the BBC explains that when you’re touched, “the nerve endings under your top layer of skin, or epidermis, send electrical signals to the brain.” And when tickled, “the somatosensory cortex picks up the signals to do with pressure, but the anterior cingulated cortex also analyses the signals. This part of the brain governs pleasurable feelings.”

Our brain then translates those signals into ones of happiness as a defense mechanism.

Evolutionary biologists and neuroscientists explain that “the part of the brain that tells us to laugh when we experience a light touch, the hypothalamus, is also the same part that tells us to expect a painful sensation. Laughing when tickled in our sensitive spots (under the arms, near the throat and under our feet) could be a defensive mechanism,” adds the same report.

Our brains have evolved over time to send this signal “to show our submission to an aggressor, to dispel a tense situation and prevent us from getting hurt,” according to research.

If you’re super ticklish and just the thought of someone’s fingers on your skin makes you chuckle, watch this video where molecular biology and genetics boffin Dr. Emily Grossman explains “how to stop yourself being ticklish.”