What toilets can teach us about user experience, as told by Y Combinator’s Kevin Hale

There’s this joke about a super drunk guy at a bar called Larry. He realizes he has to poop. The bartender tells him where the washroom is, and off he goes.

Larry lets out a scream from behind closed doors. Seconds later, he lets another one out. The bartender rushes into the toilet, bangs on the door, and asks what’s going on. “You’re scaring customers,” he says.

“I don’t know. Everytime I flush, something comes up and squeezes my nuts,” says Larry, grimacing. The bartender comes in, and realizes Larry is shitting into the mop bucket.

Kevin Hale told this story at a keynote session of Tech in Asia Singapore 2015 to illustrate a point. A toilet sink and a mop bucket share a lot of similarities. They’re both containers of water, have equivalent heights and handles, and they’re located in the bathroom.

But even sober folks are susceptible to confusion, as some lawmakers found out when they mistook a mop sink for a Muslim foot washing sink:

The joke illustrates something called false affordance. Affordance is a design concept signifying a potential action enabled by an object. Using a mop bucket as a toilet sink is an example of false affordance. In other words, it’s making wrong assumptions about what we can do with an object.

There are times when false affordances work in our favor. Many office thermostats don’t work because the air-conditioning temperature is set by a central computer. Nonetheless, it gives tenants an illusion of control – a placebo effect that leaves them contented to think actual change has occurred.

In many cases, however, it frustrates users. False affordances should generally be avoided. While many toilets do that by hiding their mop sinks, “hiding valuable features is ridiculous,” says Hale, because users should ideally find them with no trouble.

The key to eliminating false affordances lies in what’s called the intuition and knowledge spectrum: