THE next time you hear someone blaming "beer goggles" for their behaviour, you may have to believe them. People really do appear more attractive when our perceptions are changed by drinking alcohol.
There have been few previous attempts to investigate the idea that people seem to find others more attractive when drunk. In 2003, psychologists at the University of Glasgow, UK, published a study in which they asked heterosexual students in campus bars and cafés whether they had been drinking, and then got them to rate photos of people for attractiveness. While the results supported the beer goggles theory, another explanation is that regular drinkers tend to have personality traits that mean they find people more attractive, whether or not they are under the influence of alcohol at the time.
To resolve the issue, a team of researchers led by Marcus Munafò at the University of Bristol in the UK conducted a controlled experiment. They randomly assigned 84 heterosexal students to consume either a non-alcoholic lime-flavoured drink or an alcoholic beverage with a similar flavour. The exact amount of alcohol varied according to the individual but was designed to have an effect equivalent to someone weighing 70 kilograms drinking 250 millitres of wine - enough to make some students tipsy. After 15 minutes, the students were shown pictures of people their own age, from both sexes.
Both men and women who had consumed alcohol rated the faces as being more attractive than did the controls (Alcohol and Alcoholism, DOI: 10.1093/alcalc/agn065). Surprisingly, the effect was not limited to the opposite sex - volunteers who had drunk alcohol also rated people from their own sex as more attractive.
This contrasts with the Glaswegian team's results, where there was only an effect when men were looking at pictures of women, and vice versa. One explanation, says Munafò, is that alcohol-boosted perceptions of attractiveness tend to become focused on potential sexual partners in environments conducive to sexual encounters. He aims to repeat the experiment after showing students a video of people flirting in a bar, to provide some appropriate social cues.
Munafò also intends to study how the effect varies with the amount of alcohol consumed - although ethical constraints rule out exploring doses at which our ability to focus on a face breaks down. "We can look at smaller doses and we can look at slightly higher doses," he says.
As well as changing perceptions of attractiveness, alcohol also encourages us to engage in behaviour we would otherwise avoid. In a study by Robert Leeman of Yale University students reported they were more likely to engage in risky sexual acts after drinking - which could be due to alcohol lowering our inhibitions through a direct effect on the brain or by providing a convenient excuse for such behaviour.