You solved it by representing what your friend was thinking in your own mind. Since they were doing the same thing, you had a good understanding of their situation and created a representation you could negotiate with, it went something like this:
Me: “Hey, we need to meet, how would we do this if we weren’t able to communicate?”
Friend: “We would have to agree on a landmark.”
Me: “What landmarks are we both aware of?”
Friend: “Well, several, but the Eifel Tower is the most obvious.”
Me: “Eifel Tower it is! But When?
Games where participants are given incomplete information and are asked to coordinate with other players are called Schelling Games, after Thomas Schelling, a pioneer of economics and game theory. They reveal assumptions we make about other people in order to coordinate with them. Language itself requires a constant stream of such games to adjust semantic and syntactic content to meet the needs of communication with specific individuals. One might even say that much of our communication with other people is not with them at all but with a representation of them in our minds.
User Experience design is a Schelling Game. The user is trying to accomplish something relying on conventions and labels established by the designer, hoping that the designer was able to construct a clear model of what they would have to think. When this fails, a technically sophisticated user may resort to imagining what they would have done if they had been the designer. This works really well for me. Because I’m a designer, I can construct a pretty accurate replica in my head of the designer of the site for me to interrogate.
Me: “Hey, I just clicked this thing and my selection is gone. What gives?”
Designer: “Well, I was in a hurry, and I have to code front end, so being transparent with you is not my first priority. Don’t expect me to remind you of what you have already done.”
Me: “So you just delete the selection?”
Designer: “No, no, no, I keep the selection. It’s still in the cart, but you won’t see it till the end. Just enter your information and get to the last page and you’ll see it.
This does not go so well for my Mom, whose inner Shelling Game plays out like this:
Mom: “I just clicked this thing and my selection is gone, what’s happening?”
Computer Person: “Madam, you are too old to use a computer. Also, I am going to sell your credit card information to the Nation of Nigeria and you will never get your shoes.”
Mom: “I’m going to drive to the mall now.”
That people are able to coordinate their actions in a face to face transaction at all is a feat of magic requiring conventions and assumptions buried beneath layers of reflex. Building an online interaction requires re-building these concepts from scratch. Over the years, this has gotten easier, as conventions and clichés like the “shopping cart” metaphor start to become reflexively used by designers and reflexively interpreted by users. But the further we come in building this new language, the more culturally specific our designs are.
One way around this is to drive UI innovation towards metaphors rooted more deeply in the physical world. Touch screen interfaces have reduced the role of Schelling Games by shrinking the gap between the knowledge the user arrives with and the knowledge they need to use the interface. Because they can make use of motor schemas and interaction patterns used with physical objects, touch screens needn’t rely on complex control metaphors like scroll bars to do simple things like scrolling. In this way, the more advanced hardware becomes, the more primitive interaction conventions can become, but that doesn’t mean the Schelling Games are over. As long as there is an advantage to be gained from passing yet more information between humans and machines in a comprehensible and useful form, designers and users will make use of our magical ability to guess at meaning.