Image: John White

(Medical Xpress) -- It's a part of modern lore that doesnt reflect well on our species, the idea that as people consume alcoholic beverages, they see those around them as becoming more attractive. Its known as the beer goggles effect, and has been used by members of both genders to help explain sexual escapades with another person that under normal circumstances would not be someone they would consider for such activities. Now new research helps to explain how and why this happens. L.G Halsey, J.W Huber, and J.C Hardwick have published the results of their research on the topic in the journal Addiction, and suggest that one reason people find others more attractive when drinking is because alcohol impairs a persons ability to detect facial symmetry.

The team notes that prior research has shown that a part of what makes people attractive to other people is the degree to which both sides of their face match. The more symmetry, the thinking goes, the better the gene pool, hence the more desirable they are as a potential mate. This they say is one of the major factors that cause someone to see another as someone they would consider bedding. But, the whole system begins to go off the tracks when alcohol is introduced. The researchers found that the more a person consumes, the more trouble they have figuring out symmetry in the faces of those around them, causing them to see everyone as better looking than they would were they sober. This they say, accounts for the beer goggles effect.

To come to these conclusions, the team enlisted over a 100 male and female volunteers from Roehampton University who were given the task of looking at photographs and rating the degree of attractiveness of the person shown. They were also asked to rate the degree of symmetry. Some volunteers were given drinks containing alcohol, while others were given drinks with no alcohol in them at all. The faces in the photographs had been premeasured for degree of symmetry and indeed some of the photographs had been altered to force the faces to be perfectly symmetrical.

After compiling the results, the team found that those people who were consuming alcohol showed less ability to discern symmetry, and that their abilities grew worse as more alcohol was consumed. They also found that womens abilities were more strongly impacted than men.

While these results clearly show a correlation between alcohol consumption and an ability to discern facial symmetry, and perhaps degree of attractiveness, the team isnt suggesting that their results fully explain the beer goggles effect, more that their research adds a piece to the overall puzzle that is the decision making process and ultimate behavior of people when consuming alcohol.

More information: Does alcohol consumption really affect asymmetry perception? A three-armed placebo-controlled experimental study, Addiction, Accepted Article, Does alcohol consumption really affect asymmetry perception? A three-armed placebo-controlled experimental study,, Accepted Article, DOI:10.1111/j.1360-0443.2012.03807.x Abstract

Aims: A possible explanation for increased levels of attractiveness of faces when under the influence of alcohol is reduced ability to perceive bilateral asymmetry. This study tested the degree of preference by alcohol-dosed and non alcohol-dosed participants for symmetrical faces and their ability to detect facial symmetry, while controlling for other explanations.

Design: Volunteers were recruited to a random allocation experiment with three conditions: alcoholic drink (alcohol dosed), non-alcoholic drink (placebo) and diluted orange cordial (control). Data on concentration, personality and demographics were collected. Dependent variables were symmetry preference and detection.

Setting: Laboratory, University of Roehampton.

Participants: 101 participants, mainly students (41 alcohol-dosed, 40 placebo, 20 control).

Measurements: Participants provided verbal responses to images of faces which were presented on a computer screen for 5 seconds each; the first task required a preference judgement and the second task consisted of a forced-choice response of whether a face was symmetrical or not. Levels of concentration, weight and level of alcohol-dose were measured, and demographics plus additional psychological and health information were collected using a computer based questionnaire.

Findings: In contrast to a previous investigation, there was no difference in symmetry preference between conditions (p = 0.846). In agreement with previous findings, participants who had not drunk alcohol were better at detecting whether a face was symmetrical or asymmetrical (p = 0.043). Measures of concentration did not differ between conditions (p = 0.214 to 0.438). Gender did not affect ability to detect symmetry in placebo or alcohol-dosed participants (p = 0.984, 0.499); however alcohol-dosed females were shown to demonstrate greater symmetry preference than alcohol-dosed males (p = 0.004).

Conclusion: People who are alcohol-dosed are subtly less able to perceive vertical, bilateral asymmetry in faces, with gender being a possible moderating factor. Journal information: Addiction

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