(In one episode of 'Cheers", Cliff is seated at the bar describing the Buffalo Theory to his buddy, Norm. The concept is explained very well, here it is...)
"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, it is the slowest and weakest ones at the beack that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular killing of the weakest members.
In much the same way, the human brain can only operate as fast as the slowest brain cells. Now, as we know, excessive intake of alcohol kills brain cells. But naturally, it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making a brain faster and more efficient machine.
And that, Norm, is why you always feel smarter after a few beers."