While user interface designers cannot affect the shape, dimensions, or textures of the device we are working with, we can affect how people use them. The use of ergonomics is a latent factor in application design. If you don’t notice it, it means that the app is doing it right. If you do notice it, it means that the app hasn’t really addressed your needs.
Most iOS applications present some level of difficulty from a usability standpoint, because of the way buttons are laid out on the screen. The navigation bar restricts its buttons to the top left and top right corners of the screen. Tab bars, which are used to navigate between main sections of the app, limit the tap area of its buttons to the bottom of the screen. While much of this is obvious to human factors experts, it is not obvious to everybody. User Interface designers have the chance to create better apps by thinking about ergonomics. As more and more people use mobile devices, we will have to consider comfort as a larger part of the user experience. We are, in fact, designing the future.
While not all apps will call for this type of attention, it is good to think about how to make them better suited for our hands. Here are a couple of things you can think about when designing your apps:
- Start with human factors.
Don’t work backwards once everything is already laid out. Think about the human hand and where you should place buttons so that they are easy to press.
- Create apps that utilize the thumb’s rotation and tendency to move circularly.
The thumb works in arcs not lines, think about designing your interface to work well for either interaction.
- Allow for diagonal gestures
Similar to designing for the thumb you should consider how users will swipe along a diagonal not just vertical or horizontal ones.
- Limit corner buttons
Consider navigation buttons that don’t sit at the corners of the screen. How else can they be discovered?
- Make content king
Create gestures/actions that enhance the content, not ones that take away from it.
- Consider your audience
Different types of people that will be using your app. Children will have smaller hands and are likely to place it on a surface or hold the phone with two hands. The elderly or disabled may do the same.
- Be Dynamic
Design your app to act dynamically. Hardware and software platforms are constantly changing. What if the screen curves? What if there is no screen? The ergonomics of a device will change with time.
There are many apps with unique interfaces, but one that must be mentioned is Partly Cloudy, a weather app designed by Raureif. It is more accurately, a weather visualization app, that allows the user to see the temperature, wind force, precipitation and more all in a circle. The user sees future weather data by moving a toggle that swings around this circle. It’s fun to move the toggle around and around this weather circle, because you can keep going into the future without lifting a finger. Your thumb naturally moves in an arc, so the motion isn’t straining or odd.
Many of these apps are actually obeying Fitts’ Law, a principle that describes the human-computer interaction as formula in which the time required to move to a target area is a function of the distance to the target and the target size. It’s not just easier and more comfortable to include ergonomic gestures in apps. It actually decreases the amount of time you spend on an action, which for most people is a good thing.
The iPhone’s native camera app is a great example of inadequate designing for the human hand. The shutter button at the bottom of the screen creates some inconvenience for people who are trying to take a photo with one hand. Snapping a photo of Holly and Max becomes a balancing act between your fingers, even more so if you want your photo landscape rather than portrait.
While many people simply “deal with it,” there are some designers and developers who have created great apps that are actually satisfying to use because of how the interface and our fingers are working together.
Michelle Chen, UX/UI Designer at Raizlabs