A new study suggests alcohol increases sensitivity to rewarding social behaviors in men particularly, possibly explaining why men are more likely to drink excessively.
The researchers, led by Catharine Fairbairn of the University of Pittsburgh in Pennsylvania, publish their findings in the journal Clinical Psychological Science.
According to the Centers for Disease Control and Prevention (CDC), men are more likely than women to drink excessively, which comes with significant increases in risks to health and safety - including chronic diseases such as liver cirrhosis, pancreatitis, certain cancers, high blood pressure and psychological disorders.
Fairbairn and her team say researchers have hypothesized that men experience greater rewards from alcohol than women do, but previous studies - in which participants were tested when they were drinking alone - have not offered substantial evidence.
As such, for their latest study, the researchers focused on the impact of gender and alcohol on "emotional contagion," which is a social mechanism of bonding and social cohesion.
"Many men report that the majority of their social support and social bonding time occurs within the context of alcohol consumption," explains Fairbairn. "We wanted to explore the possibility that social alcohol consumption was more rewarding to men than to women - the idea that alcohol might actually 'lubricate' social interaction to a greater extent among men."
To examine an objective non-verbal indicator of social bonding in the wake of group drinking, the team focused on the infectiousness of genuine smiles - known as Duchenne smiles, which involve the muscles around the mouth and eyes - in study participants.
They explain that Duchenne smiles are linked to genuine felt emotion, in contrast to outward displays of emotion, which may not necessarily be genuine. What is more, a standardized procedure can accurately identify and measure these smiles.
Alcohol increased smile contagion in all-male groups
In total, 720 participants between the ages of 21-28 took part in the study; 360 were male and 360 were female. The researchers randomly assigned the participants to one of three groups: those receiving an alcoholic beverage (vodka cranberry), those receiving a non-alcoholic beverage, and those receiving what they thought was an alcoholic beverage, which was actually a non-alcoholic placebo.
The placebo beverage was served in a glass smeared with vodka and contained a few drops of vodka floating on top, in order to make it more believable.
Then, in smaller groups, participants were positioned around a table and casually introduced as the beverages were served in equal parts over time. The men and women were told to consume their drinks at an even rate, but other than that, they were not given any specific instructions so as to encourage free interaction.
Fairbairn and her team analyzed video recordings of the interactions using analyses that modeled smiling behavior, following the spread of smiles from one participant to the next.
Results of their analysis revealed that alcohol "significantly" increased smile contagion, but only in all-male groups; interestingly, it did not affect emotional contagion for groups containing any women.
The team says their findings suggest alcohol prompts "social bravery" among men in particular, interrupting processes that might normally stop them from responding to another person's smile.
'Creating social bonds is a fundamental human motive'
Additional findings showed that in the groups that received alcoholic beverages, a smile was more contagious if the individuals on the receiving end of it were heavier drinkers - whether male or female.
And among the sober groups, Duchenne smiles were much less "infectious" among all-male groups than all-female groups.
The researchers say smiles that caught on were linked with increased positive mood and social bonding and decreased negative mood, which suggests smile infection could be an important indicator of alcohol reinforcement, supporting drinking.
"Historically, neither the scientific community nor the general public has been terribly concerned about drinking that occurs in social settings," says Fairbairn. "According to popular opinion, a 'social drinker' is necessarily a non-problem drinker, despite the fact that the majority of alcohol consumption for both light drinkers and problem drinkers occurs in a social context."
She adds that "the need to 'belong' and create social bonds with others is a fundamental human motive. Therefore, social motives may be highly relevant to the understanding of how alcohol problems develop."
When asked about potential public health efforts aimed at reducing excessive drinking among men, Fairbairn told Medical News Today:
"Research has long shown that societal conceptualizations of 'manliness' are often at odds with male expressions of intimacy, warmth and closeness. It's possible that the social limits we place on men push them toward drinking as a means of bonding with others (although the results of this study can't speak to that directly).
In terms of interventions, it could be helpful to create more outlets where men can get to know one another socially without alcohol - cultural spaces where creating close relationships doesn't come into conflict with masculinity."
MNT recently reported on a study that suggested we drink more alcohol on days when we are more active.