Today, I discovered yet again one of the cardinal sins of user interface design – inconsistency. A blog had two pagination interfaces on one page - and they had opposite directionality. For one, older posts were to the left; for the other, older posts were to the right. This is an obvious and egregious error, and the solution is to make them operate in the same direction, or better yet, remove one.
But can we do better than that? Which direction should be older posts, and which should be newer posts? Well, that’s a question my first area of study (psychology) can answer. I don’t know if this question has been asked specifically, but there are certainly clues in psycholinguistics.
Lera Boroditsky’s talk at the Long Now conference (which you should watch in its entirety) mentioned that English speakers gesture to indicate temporal sequences from left to right, in accordance with the directionality of the writing system used in English. Chinese speakers showed the same preference. Experiments show that there are significant cross-linguistic differences in how spatial metaphor is used to talk about time.
So, shouldn’t forward/back buttons be oriented in accordance with these linguistically-differentiated preferences? For English speakers, back goes on the left and forward goes on the right. Same for Chinese – unless the buttons are vertically aligned, in which case Chinese speakers want the past to be on top and the future to be on the bottom. This is a simple enough conclusion, arrived at by studying human psychology.
User interface design is really about human-computer interaction, and is just as much about understanding the human as the computer. Software developers and user interface designers should pay attention to cognitive psychology – it can reveal important facts about human cognition that can help us design better software.