There is a simple answer. Scientists are writing studies about the people they selected to drink from glasses they marked with squeaky markers but... there is a simpler answer:
The results showed that the markings slowed the speed at which people drank. The group with the marked glasses took an average of 10.3 minutes to finish their pints, while the non-marked glass group took 9.1 minutes. Dr Angela Attwood said: “The speed at which beer is drunk can have a direct effect on the level of intoxication experienced. This can also increase how much is consumed in a single drinking session. While many people drink alcohol responsibly, it is not difficult to have 'one too many' and become intoxicated.
Simplicty itself! What the eggheads in lab coats missed is the gap. The passage of time. The wait for the next drink. Dr. Hugh McQuestionmark and all the other brainiacs have latched onto the difference between a straight glass and a curved one to define which one goes down faster. Oh, simple science. All the powers of new-prohibitionists, nanny state public healthers and the tisking librarian from your high school just need to band together in an unholy alliance to infiltrate barroom server schools and teach the slow dance, the widening of the gap from drink to drink. Then everything will be swell. We'll drink less. Right?
Oddly, this is the second curved v. straight sided study I've come across. The odder thing is they contradict each other. A curved side makes a pint go down 1.2 minutes faster now but in 2012 the difference between two similarly differences half pints was four minutes. Four! What the hell is that about? If I was Manager of Science up in the office above the industrial scientist workshop floor I'd likely shout that a lot: "WHAT THE HELL IS THAT ABOUT?!?!" They'd talk about me at break time but I wouldn't care. Not a bit.