Pot heads are mellow, drunks can be mean. That's the common wisdom, and now, thanks to a group of researchers from the Netherlands, it has some scientific validation. In a just-published study in the journal Psychopharmacology, they found that—doh!—people on booze act out, while people on pot peacefully space out.

"The results in the present study support the hypothesis that acute alcohol intoxication increases feelings of aggression and that acute cannabis intoxication reduces feelings of aggression," the researchers concluded.

The study itself sounds like fun. In a random, controlled trial, the researchers recruited 21 heavy pot smokers (at least three times a week), 20 heavy drinkers (at least three drinks a day for men, two for women), and a control group of 20 who used neither substance heavily.

They then had the drinkers drink until they were too drunk to legally drive (0.08% blood alcohol level) and the tokers vape up 300 micrograms of THC per kilogram of body weight, enough to get them nicely baked. The control group, being the control group, missed out on the intoxicants.

Then all three groups completed a number of tests designed to get people wound up. In one, subjects played a computer game in which the object was to win money by pressing buttons, but players' efforts were undermined by an "adversary" that took money from them. The adversary was actually part of the computer program. In a second test, known as a "single category implicit association test," subjects were shown images of violent and aggressive behavior and asked to match positive and negative words to the photos.

The researchers measured aggression by asking the subjects to rate how aggressive they felt on a 100-point scale, and weighed that against a baseline score established by asking them the same question before they had gotten wasted. And they ran the tests one more time a week later, with the same subjects, but without getting them high or drunk.

"Alcohol intoxication increased subjective aggression in the alcohol group," the researchers found, but pot smokers became less aggressive when baked.

It wasn't just subjective. While alcohol drinkers rated themselves as more aggressive when drunk, they were also found to be objectively more aggressive, as measured by their willingness to undermine their opponents in the computer game.

We already know that marijuana is a less harmful drug than alcohol, being both far less toxic and less addictive than booze. And now we get some scientific backing for something else that was already patently obvious.