Sloshed, trollied, hammered, plastered. We’ve done a sterling job of inventing words for the inebriated state, but when it comes to judging from their behaviour how much a person has drunk, we could do (a lot) better. That’s according to a review of the literature by US psychologist Steve Rubenzer.

We all have our trusted indices for judging other people’s drunkenness. Perhaps it’s when the eyeballs start floating about as if under the control of a clumsy puppeteer. Or maybe the effusive ‘you know I love you’ delivered with a trickle of dribble. However, the vast majority of studies find that lay people, police officers and bartenders are in fact hopeless at distinguishing a drunk person from a sober one, at least at moderate levels of intoxication. To take just one example, after watching drunk and sober people being interviewed and negotiating a stair case, bartenders rated them as slightly, moderately or very drunk with an accuracy of just 25 per cent…