system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does having water dumped on your head make you lose your breath?
gpt
It replicates the sensation of falling into a pool of water or the ocean and provokes an unconscious reaction to hold your breath because you will drown if you breath in the water.

This reaction can also be seen in babies. When people say "babies can swim", what actually happens is when the baby goes into the water, they hold their breath until they resurface and are able to breath.

In evolutionary terms if you fall in some water and continue breathing, you will drown. People who developed this reaction survived to pass on their genes.