In an episode of "Cheers," Cliff explains the Buffalo Theory to his friend Norm at the bar:
"Well, you see, Norm, it's like this... A herd of buffalo can only move as fast as the slowest buffalo. When the herd is hunted, the slowest and weakest ones at the back are killed first. This natural selection benefits the herd overall, as the group's general speed and health improve through the regular elimination of its weakest members.
Similarly, the human brain can only operate as fast as its slowest brain cells. Excessive intake of alcohol kills brain cells, but it naturally attacks the slowest and weakest ones first. Thus, regular beer consumption eliminates weaker brain cells, making the brain a faster and more efficient machine.
And that, Norm, is why you always feel smarter after a few beers."