Wednesday, September 02, 2009

Mind Games with Vending Machines

In previous break room adventures, I explained how the snack vending machine was forced to give up my bag of Doritos in a multi-person strike team effort, and today, a colleague explained to me that the soda vending machine is schizophrenic. I never buy drinks there, so I asked, how so?

Apparently, it charges a different amount each time. I commented that perhaps it was because each drink was priced differently, but no, he ordered the same Pepsi One every time. As we stood in front of the machine, I checked out the price. Officially, 65 cents for a soda.

On the previous day, he’d been charged 90 cents. A dollar was inserted, and the machine did its fancy thing, sending a mechanical picker-upper zipping across to retrieve the can and bring it to the opening, avoiding the dreaded drop-and-create-carbonation-mess that lesser (yet more reliable) machines perform. We heard the change clank. And clank. And clank.

$1.20 back in change. “Hey!” said my friend, “Across two drinks, I’m still ahead.”

“Oooh! This is Vending Machine Roulette! Have you read those studies about how behavior is changed when there is an uncertain outcome? These psychologists gave rats the option to press two bars for food. One bar gave a single pellet each time. The other bar would give zero, one, two, or three pellets at different probabilities, and the rats got addicted to pressing the bar because they might, just might win big. The vending machine is training you to buy more drinks because you want to see what will happen!”

My colleague was not as amused as me, but at least he got his change back this time.

*I couldn’t find the pop science article reference, and this more scholarly paper has a more complicated story than what I remembered, but hey, I still think it would be an interesting business to see if people start to “play” the vending machine like slots.


Bob said...

Funny story and great observation.

Asianmommy said...

How funny!

mayberry said...

I guess he needs to meet Lady O if he is insulted to be compared to a rat!

Anonymous said...

Great story!

I think you might find something more pop-psych and less scholarly if you search under variable ratio reinforcement schedule (or some such combo).


Anonymous said...

I read somewhere that Pepsi had experimented with some machines that charge more on a hot day and less on a cool day. They were hated upon inception. I wonder if you guys got an old machine. One more variable for your coworker to track :)

Fourth B

Amber said...

I guarantee you there would be people who would buy a drink just to see what change they would get. People gamble on far lesser things every day, with no cool beverage to show for it.

Mom101 said...

That's awesome. Suddenly I want to go throw down some coin and cross my fingers for some Cracker Jacks