It’s a gorgeous Canadian night…one of the few relatively warm nights we have left and I’m heading out for a night of drinking. Despite the incredible joy alcohol brings me, I try not to drink more than a couple nights a year because I strongly believe alcohol has an absolutely devastating long-term effect on fluid intelligence, and to a lesser extent, crystallized intelligence too…I would estimate that regular alcohol consumption subtracts about 5 fluid IQ points a decade. By middle age, alcoholics often can not complete a spoken sentence extemporaneously.
Here’s a terrifying personal account of the effects of alcohol on the intellect, written by comper26 at yahoo answers:
chronic drinking like 750ml of vodka a day for many years will not help. After many years of doing this I sometimes cannot remember what clothes I wore a day earlier or what I had for breakfast just hours earlier so it will definitely fry brain cells over the long term. I am still kind of short on memory 6 months after I gave up my very pleasurable hobby of heavy drinking.
If iq is based on what you’ve learned or memorized, then you will slowly lose knowledge of things you’ve learned after years of doing it…the good news is that your long term memory may remain decent even after years of drinking but your short term memory may suffer the consequences. Even long term memories like childhood events, song lyrics, movies you used to be able to quote lines out of…that all slowly slips away if you drink heavily for years.
I think people with large cranial capacities can probably get away with drinking more, not that I would recommend any big headed people do so, especially since not all big heads reflect large brains (some reflect thick skulls, others reflect autism where the brain was large in childhood, but is actually small in adulthood; though the head remains large as a fossil of the large childhood brain). Big brains are not only more intelligent, but probably have more cognitive reserve, even independently of their IQ.