Focusing on one conversation in a loud, distracting environment is called "the cocktail party effect".
It is a common festive phenomenon and of interest to researchers seeking to improve speech recognition technology.
Neuroscientists recorded from people's brains during a test that recreated the moment when unintelligible speech suddenly makes sense.
A team measured people's brain activity as the words of a previously unintelligible sentence suddenly became clear when a subject was told the meaning of the "garbled speech".
