Affordances, Signifiers, and Moscow Mules
I take pride in really caring about the design of the software I build. I can usually tell when it’s good, when the visuals and interactions are dialled in; but, I rarely have a clear idea of how to get there.
Thankfully, I’ve been lucky over the years to work with some really great designers1 who have helped show me the way.
In an effort to learn some more of their language I’ve been reading ‘The Design of Everyday Things’. So far it’s a very interesting read. An analysis of the design and psychology of everyday things. I–like many no doubt– share his ceaseless frustration with poorly designed doors; the ones that fail to signal whether I should push or pull them.
This video about these so called ‘norman doors’ from vox - lead me to the book:
The first few chapters introduce two basic terms ‘Affordances’ and ‘Signifiers’:
An affordance is a relation between an object or an environment and an organism that, through a collection of stimuli, affords the opportunity for that organism to perform an action. For example, a knob affords twisting, and perhaps pushing, while a cord affords pulling. As a relation, an affordance exhibits the possibility of some action, and is not a property of either an organism or its environment alone.2.
Affordances define what actions are possible. Signifiers specify how people discover those possibilities: signifiers are signs, perceptible signals of what can be done. Signifiers are of far more importance to designers than are affordances.3.
Confounded By Limes
Now, I’m by no means an expert after reading a third of the book, so I’m pretty unlikely to add much to any conversation on these two words. But, I did want to share a funny story that immediately came to my mind as I was reading.
When I first met James he was very into Moscow Mules. It should surprise no one that James’ mule game was–On Point. He’d sorted out the best Jamaican ginger beer, may have even been ordering it by the crate, but the one thing we couldn’t get a handle on was this top of the line lime juicer he had, the FreshForce™ Lime Juicer.
While it may be obvious from this picture above that you put the lime in face down, it took us weeks and many shots of lime to the eye to come to that conclusion. The signifying lure of that hemisphere was too great for us to ignore, like a siren singing us to our citrusey doom.
Now you might be saying we should have just read the instructions–in this case you’re probably right–but just the same one of the differences between a good design and a great design is the latter doesn’t let you do it the wrong way. The juicer afforded me the ability to squish a lime, but it signified that I aught to match the shape of the lime to the shape of the juicer. The design should have assumed–quite correctly–that I might not possess the deductive reasoning to try the one other possible state of the lime position, and rather disallowed any illegal states.
The lessons of affordance, signifiers, and discoverability need not be limited to visual and interaction design. Software developers can take the lessons of the FreshForce into their APIs, making it hard for another developer to use your gem, jar, or JSON service in the ‘wrong’ way will make up for the inevitable lack or staleness of documentation.