The jog dial has found its way onto most electronic devices–cameras, computer mice, and cell phones to name a few–with varying results and consumer reactions. My first digital camera, the Sony Cyber-Shot, came equipped with a jog dial for scrolling through pictures and settings, and pressing in on the dial selected images and selected menu options. Nikon cameras make use of their jog dials by combining the scroll feature with various buttons to enable power users to make complex adjustments much faster than a traditional menu system would allow.
I’ve owned quite a few portable media players in the past decade, and one that’s stood out is the relatively cheap Sansa e140–stood out, primarily, because it outlasted most of the other relatively cheap models that decided to stop working with months of purchasing them. The e140 is notable in that it sports a typical jog dial in a less typical location: the corner of the unit.
I’m sure the designers who came up with this idea figured the corner placement would allow users to access the dial in two different ways: with the thumb along the side . . .
. . . and with the index finger along the top.
Seems like a pretty solid concept. But there’s one thing about a rotational input that doesn’t exactly lend itself to this kind of placement.
The jog dial serves two distinct tasks on this player: to navigate the menu system and to control playback volume. Other devices, like the iPod, use this same approach, but here’s where it gets tricky.
When using the menu to find songs and change the player’s settings, the dial acts like this:
As the dial rotates downward, the selection bar moves down the menu. So far so good. Now let’s take a look at the same dial’s behavior when changing the player’s volume.
Why does it do this? It really seems out of place for the dial to be playing Opposite Day when it comes to volume control, but acting perfectly normal with everything else. There’s only one reason I can come up with to explain it. Perhaps the designers decided that most users would be holding the player in a pocket, or at least in a different position, when adjusting the volume. If you think about it this way . . .
. . . it makes a lot more sense. And here we find the inherent problem with corner-mounted jog dials. They violate an unwritten yet important rule in ergonomics:
Up goes with Left; Down goes with Right.
Sure, turning the dial to the right increases the volume, which makes sense, but that’s also turning the dial downward, which makes no sense at all. At the same time, the entire dial is rotating to the right, so if you view it as a volume knob, it’s doing its job properly. But without being able to view it like a knob, who’s going to imagine it that way?
It’s most likely different in other cultures, but because we read top to bottom and left to right, we want to equate those directions respectively. Moving up and left are typically regressive movements in menu navigation.
There are several exceptions to this rule. Television remote controls, for example, either display the channel buttons as left and right or up and down, and in this case, up goes with right, down with left. But in most other cases, it’s the other way around. Not just with navigation, but displaying information as well. Take a look at how both Windows and OSX arrange files within a folder. In both environments, a horizontal view will place the first file on the left, while a vertical view places it at the top.
I don’t know why the e140′s jog dial bothers me so much. I’m the sort of person who can remember the idiosyncrasies of a system and use it just as easily as if everything were perfectly consistent, but the whole idea of putting the dial in the corner, while apparently offering more access to the user, does nothing but add confusion.
If Sandisk, the manufacturer of the player, still wished to place their jog dial in the corner of the device, there are two corners more sufficient for the job: the upper left and the lower right. This way, an upward action and a rightward action would match. However, putting the dial along the lower right would cause a completely different kind of confusion: viewing the dial like a volume knob, if a user could visualize it that way, you’d then be rotating the knob to the left to turn the volume up.
So the only remaining option would be to place it in the upper left corner. Sure, most users are right-handed, but the player’s small enough to reach each corner no matter how you hold it. Still, it would be more ergonomically awkward to put it there, so the only conclusion should be to ditch the corner-mounted jog dial, at least until a better application arises. But a music player just doesn’t need it.