One of the tests involved looking at faces and stating whether they thought each one was symmetrical or non-symmetrical.
Scientists have long known symmetry to be tied to attraction, with a face in which one half mirrors the other seen as a sign of good genes and good health.
The men and women given the vodka and tonic found it more difficult to work out if a face was symmetrical than those on soft drinks.
Researcher Lewis Halsey said: 'People that had drink tended to be less good at noticing if a face was asymmetrical, they often saw it as being symmetrical when it was asymmetrical.'
And the women drinkers were particularly bad at the task, the journal Addiction reports.
Dr Halsey said: 'What we have shown is that people's ability to detect symmetry is part of the explanation for the beer goggle effect.
'The consequences could be considerable. A lot of people say they met their partner when they were drunk. Are their marriages shorter or longer lasting? Does it change the nature of the relationship?' The study is not the first to probe the beer goggles phenomenon.
A Bristol University study found people do appear more attractive to both sexes after they've had a drink - and it takes as little as a pint and a half of beer.
In some cases, the mere anticipation of alcohol may be enough to alter judgement.
A U.S. study showed that men rated pictures of women more highly after looking at alcohol-related words than phrases about coffee and soft drinks.
Researcher Professor Ronald Friedman said: 'We propose to have found a case of automatic "beer goggling".'
But other research has disputed the phenomenon, with a British study concluding that men find women no prettier after drinking.
The Leicester University researchers said: 'There was no difference - the men were just as undiscerning as ever.'