The incredible flipping preference

What we truly prefer is sometimes not what we choose

There is a new coffee place in town. Monday last week temptation got the better of me and I decided to try it out. The Americano was rather pricey at £3.50, but it tasted so very nice, that I went back the next day. The barista is an intriguing person, with an extraordinary memory. Having seen me only once before, she still immediately greeted me by my (admittedly unusual) name. She also has a rather peculiar way of proving that her coffee, costly as it is, is the best value for money.

On that second day, she made me an offer. She would dilute her coffee by 2% and charge me 10p less, and let me compare that with the standard full strength coffee. If preferred the newer one, I would be guaranteed to always get that cheaper variant — just 2% diluted, but at 10p less. So I watched her do her magic, and then sipped alternatingly from the two cups in front of me. Much as I tried, I could not really spot any difference, so rational dude that I am, I went for the cheaper version.

“I thought you would,” the barista said. I smiled, and worked out that I’d just saved myself £25 on my annual coffee budget.

Keep on diluting

On Wednesday, she made me the same offer: reduce the strength by a further 2%, and another 10p discount, if I preferred this version over Tuesday’s. Once more, I couldn’t notice a difference between today’s and yesterday’s variants, so as before I decided to go for the cheaper coffee. “I thought you would,” she said again, with a twinkle in her eye. I was now going to save £50 a year on my daily coffee. Great!

Thursday, and Friday, the same story.

So the next Monday, one week after my first visit, I was wondering whether she’d be proposing to reduce the strength further, until I’d stick with my last preference. And indeed she asked, “You preferred Friday’s version over all the coffees you tried last week, right?” I nodded. I was now drinking coffee that unnoticeably little less strong, but I was paying 40p less per cup. That would save me more than £100 per year — the price of a very nice meal for two.

“Here it is again, and here’s a cup of my standard coffee to compare it with,” she…