A herd of buffalo can only move as fast as the slowest buffalo. And when the herd is hunted, it is the slowest and weakest ones at the rear that are killed. This natural selection is good for the herd as a whole because only the fittest survive thus improving the general health and speed of the entire herd.
In much the same way the human brain only operates as quickly as the slowest of it’s brain cells. Excessive intake of alcohol kills brain cells, as we all know, and naturally the alcohol attacks the slowest/weakest cells first.
So it is as plain as the nose on your face that regular consumption of Guinness will eliminate the weaker, slower brain cells thus leaving the remaining cells the best in the brain.
The end result, of course, is a faster more efficient brain.
If you doubt this at all, tell me, isn’t it true that we always feel a bit smarter after a few pints?