Of course, there is a lot going on there. The music adds to the atmosphere. Many of the people who are there know each other, and so they are continuing conversations that have been going on for weeks (if not years).

What role does alcohol play in this?

This question was addressed in a paper by Michael Sayette and 8 of his colleagues in paper in the August, 2012 issue of Psychological Science. They did a fascinating and well-designed study of the influence of alcohol on social interactions.

A total of 720 people participated in this research. One set of participants drank about 3 drinks over a 30 minute period. The drinks were a mixture of vodka and cranberry juice. The second set drank 3 drinks. The placebo was a mixture of flat soda and cranberry juice. Before participants entered the lab, though, the glasses were wiped with vodka to give them an alcohol taste. The third set drank cranberry juice and was told that they were given no alcohol. The reasoning behind these three groups is that it helps to distinguish between the effects of alcohol and the effects about the belief that you are drinking.

Participants came to the lab in groups of three. The experimenters ensured that the group members had never met before. Participants sat around a table to consume their drinks. They thought that the purpose of the study was to test the effects of alcohol on other tasks that they would do later, but the experimenters were really interested in the interactions among people as they drank and how that affected how much the group members got along with each other.

After finishing their drinks, the group members filled out evaluations of how much they liked the other members of their group.

What happened?

First, the manipulations of the drinks worked as expected. Participants in the alcohol condition had the highest blood alcohol levels (about .06 by the end of the study). The other two sets of participants had very low blood alcohol levels. Second, both the alcohol and placebo participants rated themselves as feeling somewhat intoxicated, though the participants who drank alcohol rated themselves as much more intoxicated than those in the placebo group. Consistent with that, the alcohol participants estimated that they drank about 7 ounces of alcohol, while the placebo participants estimated that they drank about 4.5 ounces of alcohol.

Overall, the people who drank alcohol rated that they got along better with their group members than either the people who drank the placebo or the non- drinks. The difference between those who drank alcohol and those who drank the placebo was particularly large.

Why did this happen?

The researchers did a painstaking analysis of the facial expressions of the group members and the speech patterns. The groups that drank alcohol smiled more and gave fewer signs of negative feeling than the other groups. So, on a moment-by-moment basis, the groups that drank alcohol seemed to be having a better time than the other groups.

In addition, everyone in the groups that drank alcohol seemed to participate in the conversations to a greater degree than the people in the other groups. In the groups that drank alcohol, there were more conversations in which each person took a turn speaking.

Putting all of this together, then, a moderate amount of drinking gets people to participate in social interactions and to enjoy those social interactions. In that way, alcohol helps people to get along well with others. This seems to be an effect of the alcohol itself, and not just the belief that you are having alcoholic drinks with other people, because the results of the placebo condition were similar to those of the control condition.

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