The human brain sends hundreds of billions of neural signals each second. It’s an extraordinarily complex feat. A healthy brain must establish an enormous number of correct connections and ensure that they remain accurate for the entire period of the information transfer—that can take seconds, which in “brain time” is pretty long.
How does each signal get to its intended destination? The challenge for your brain is similar to what you’re faced with when trying to engage in conversation at a noisy cocktail party. You’re able to focus on the person you’re talking to and “mute” the other discussions. This phenomenon is selective hearing—what’s called the cocktail party effect.
When everyone at a large, crowded party talks at roughly the same loudness, the average sound level of the person you’re speaking with is about equal to the average level of all the other partygoers’ chatter combined. If it were a satellite TV system, this roughly equal balance of desired signal and background noise would result in poor reception. Nevertheless, this balance is good enough to let you understand conversation at a bustling party.