We now have solid scientific evidence that people are completely unable to determine how soused they are when drinking with a group. A team of social scientists recently completed a study of bar and club hoppers in Cardiff, Wales and discovered that most had incredibly inaccurate notions of their drunkenness and the dangers of drinking. But the researchers also learned something non-obvious and intriguing about how people estimate their levels of inebriation.

In a BMC Public Health paper, the researchers write that they wanted to know "how people judge their drunkenness and the health consequences of their drinking whilst they are intoxicated in social drinking environments." So they spent several months going to four different party neighborhoods in Cardiff between 8pm and 3am on Friday and Saturday nights. These neighborhoods had, as the researchers put it, "a high density of premises licensed for the on-site sale and consumption of alcohol." To get a broad sample of bar hoppers, researchers would approach every seventh person they saw and ask them to participate in the survey. The idea was to try to get people who were out with different social groups, because the researchers were interested in how peers influenced people's subjective experience of drunkenness.

Once a Cardiff drinker agreed to participate, the researchers would administer a blood alcohol test to determine their actual level of inebriation. Then they would ask the drinker a series of four questions:

1) How drunk are you right now, on a 1 (totally sober) to 10 (completely drunk) scale? 2) How extreme has your drinking been tonight, on a 1 (not at all) to 10 (completely extreme) scale?” 3) If you drank as much as you have tonight every week, how likely is it that you will damage your health in the next 15 years, on a 1 (definitely will not) to 10 (definitely will) scale? 4) If you drank as much as you have tonight every week how likely is it that you will get cirrhosis of the liver in the next 15 years, on a 1 (definitely will not) to 10 (definitely will) scale?