A lot of research suggests that alcohol should be bad for sex. Scientists have measured how alcohol affects penile swelling, vaginal engorgement, time required to achieve orgasm (both during intercourse and masturbation) and vaginal lubrication. The results? Alcohol inhibits all of these sexual responses. Erections are slower to rise and quicker to fall, vaginas are slower to lubricate, and orgasms are delayed.
And yet many people report that moderate amounts of alcohol are good for sex. In one of the largest surveys addressing the issue, 45% of men and 68% of women said that alcohol enhances their sexual enjoyment.
So what’s going on? The answer to this apparent paradox lies in the old joke that the brain is the body's largest sex organ. Especially where alcohol is concerned, this is no joke at all – as about 40 male undergraduates from Rutgers ably demonstrated in a classic experiment conducted in 1976. It worked like this.
The male students were divided into 4 groups. One group was given vodka and tonic and were told it was vodka and tonic. Another group got just tonic, and were also told the truth about what they were drinking. The third and fourth groups, however, were lied to. The third group of men got vodka and tonic, but were told (and were led to believe by some simple tricks) that they were drinking plain tonic water. The last group was told they were getting alcohol, but in fact they simply got tonic water served to them in glasses smeared with a few drops of vodka to produce an alcohol smell.
After downing their drinks, each volunteer was outfitted with a variety of monitors to measure things like temperature, heart rate, and penile swelling. Thus wired, they settled in to watch an erotic video.
The results were striking. The subjects who thought they drank alcohol were most highly aroused – whether they actually consumed alcohol or not. The men who thought they drank alcohol and who actually got alcohol were the most highly aroused, while the men who thought they got alcohol but got only tonic were slightly less aroused, but still significantly more aroused than those who either got, or thought they got, tonic water. It was the belief in alcohol consumption that proved significant for sexual response, not the presence or absence of alcohol. The belief overcame any of the physiological dampening effects the alcohol might have had.
When it comes to alcohol, in other words, people quite often feel what they expect to feel. This process can obviously be self-reinforcing. The experience of an enhanced sexual encounter under the influence of alcohol can lead to increased expectancies of similar results the next time around.
Now, I’m not saying that alcohol has no effect at all. It most certainly does, as Shakespeare noted more than 400 years ago when he had the Porter in Macbeth observe that drink “provokes the desire, but it takes away the performance." All of the research on expectation and alcohol on sexual response used moderate amounts of booze. The blood alcohol levels among the Rutgers men, for instance, were equivalent to what would be found after the consumption of only 2 or 3 standard drinks over the course of an hour. (A standard drink is defined as a half-ounce of pure alcohol – the amount generally found in a can of beer, a 5 oz. glass of wine, or a 1.5 oz. shot of whiskey.)
If higher doses had been used in the experiments, it's likely that all the physical variables measured, including penile swelling, would be adversely affected. There are limits, in other words, to mind over matter. Given a high enough dose, all the expectation in the world won't rouse a penis (or clitoris) anesthetized by alcohol. A little alcohol may be good for desire, but too much will take away the ability.