At the Grand Central Terminal in New York City, if you venture downstairs to the food court, you'll find a women's bathroom.

There's a sign in the doorway that says:

RULES OF CONDUCT

NO smoking

NO bathing or laundering

NO littering

NO drinking alcoholic beverages

Violators subject to fine, removal from premises or issuance of a criminal court summons

If there's a sign, it means people try this, which means it's normal

The bathroom is a little disheveled. But having a printed sign that tells people not to bathe in the sink says something about what people have tried to do. When a user sees the sign, they're going to assume that:

(a) Others have tried to do it, and this is a place where that's common and at least kind of normal.

(b) Because it's common, it wouldn't be the craziest thing in the world if I tried to do it, too.

People like us in places like this

There's a study that shows that people actually litter more at the beach when you tell them not to litter, if you explain that everyone else does it.

People behave based on what their peer groups do. It's the concept of "people like us do things like this." I like to call it PLU (people like us) for short (credit goes to my boss for inventing the phrase).

I'll riff on that and add that people take cues from places like this (PLT).

What's considered normal and acceptable in the Grand Central bathroom. Apparently, attempting to bathe in the sink.

"What kind of place is this?"

With one simple sign, you signal a whole lot of things about the customers that visit, and how literal you have to be to tell people not to do certain things.

Which begs the question: what do your signs say about you?

Are you actually discouraging bad behavior?

The sign probably exists because the Grand Central building administration want to be able to cite the clearly-posted sign when someone inevitably tries something shady.

But does the sign actually get through to the person who would want to bathe in the sink in the first place? Or does it make everyone else feel strange? If putting up a sign solves the problem at the expense of everyone else feeling weird, perhaps that's worth it.

The worst case though, would be if people who would bathe in sinks decide to do it anyway because they don't care about signs. In the meantime, you alienate everyone else with the sign too.

Encouraging the right kind of behavior

One smart reader, Charles Starrett, asked, "What could be the story behind this rule, and what needs/opportunities might it point to?"

It's frustrating and sad that homeless people often must bathe in public bathrooms because they have no other options. With the lack of other infrastructure, it puts public places like Grand Central in a bind because they have to find ways to maintain the facilities and create a positive experience for everyone.

The availability of resources for the homelessness is clearly an issue that warrants a broader solution, so that signs like this don't need to be put up in the first place. I'm not attempting to tackle that behemoth of a topic here, nor discuss whether it's morally good or bad. I'm simply deconstructing how effective signage is for the use case of Grand Central trying to shape user behavior.

How do you encourage the right kind of behavior? Is there something other than signage that would be more effective?