Mental Floss

Math explains the "beer goggles" effect

Ransom Riggs

Yes, it seems there's a formula to explain everything nowadays -- including why we sometimes give people we wouldn't normally be attracted to our phone number in bars. (And, for that matter, why we get as many numbers as we do -- flossers that we are.) Now, we know what you're going to say: you don't need math to explain that; it's the beer, silly! And you'd be right, but there's more to it than that. Check it out:

Researchers at Manchester University credit the light level of the bar or club in question, the distance between two people, the drinker's eyesight and the smokiness of the room as additional factors, and when they combine all those measurements with the amount of beer a subject has consumed, they can calculate how much the "beer goggles" effect is skewing one's judgment. The formula can work out a final score, ranging from less than one - where there is no beer goggle effect - to more than 100. A rating between 1 and 50 would mean you're likely to find someone you're not attracted to less, shall we say, visually offensive than in other situations. If you're scoring between 51 and 100, it might be time to call it a night; unappealing people are looking very good to you. In case you want to test it out this Friday night, here's the formula, and its key:

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  • An = number of units of alcohol consumed
  • S = smokiness of the room (graded from 0-10, where 0 clear air; 10 extremely smoky)
  • L = luminance of 'person of interest' (candelas per square meter; typically 1 pitch black; 150 as seen in normal room lighting)
  • Vo = Snellen visual acuity (6/6 normal; 6/12 just meets driving standard)
  • d = distance from 'person of interest' (meters; 0.5 to 3 meters)