Recently, the authors of many thematic resources claim that the new iPhone 6 will force specialists to change the approach to UI-design of mobile phones.
Well, maybe it refers to the developers who specialize exclusively in iOS and do not pay attention to the rest of the world.
However, wide-screen portable devices have been around for a long time, and designers designing for all platforms take this factor into account at least since 2011.
Big touch devices have been around since Apple Newton’s 5.25-inch screen. Already in 2014, about a third of the smartphones sold had a screen larger than 5 inches in diagonal – even before Apple joined the general trend. Both in global sales and in the U.S., widescreen phones are gaining power, so you can gather enough information about the consumer habits of users of this segment.
Since Samsung created the market for widescreen devices through the launch of the Galaxy Note line, many people have been calling large-size smartphones phablet (tablet). As soon as these devices appeared on the market for the first time, UX-designers and journalists began to ironize – and not only over the name, but also over the concept.
As you can see, the phablets are becoming part of everyday life. Marketers and designers should take into account that mobile devices that people wear in their pockets or bags can have a screen size ranging from 3.5 to 6 inches.
Why do people control the phone with one hand?
It is generally accepted that the 3.5-inch screen of the iPhone is the ideal size for a smartphone, and it is assumed that other formats do not fit into your hand. The idea behind Figure 2 is that people feel comfortable touching the areas they don’t have to reach for with their thumbs.
But even ignoring the fact that people run many smartphone functions with both hands, this assumption still remains incorrect. We don’t feel uncomfortable when we reach for the right place on the screen, just because it’s impossible – there are limits that people can’t reach.
It’s easy to see that smartphone users are constantly adjusting the position of the device in their hands to make it easier to interact with the rest of the screen.
The sales figures mentioned above show that people do not object to this “inconvenience. Users continue to buy large devices, and this does not mean that the modern generation has any special hands. As part of this study, many participants use their second hand to facilitate navigation.
No one complains about this – even when testing iPhone users, who are given a larger Android phone – they just adapt.
People use smartphones differently
A number of studies can clarify how people hold their phones and adjust the hand position for a 5.1-inch device, a small pablet. In a recent article, Mikkel Schmidt raised a similar question about single-handed devices and organized his own research on the speed of clicking on the iPhone 5S – a 4-inch phone.
Both studies have similar results, as can be seen in Figure 3.
This study of mobile device screen control – including thumb speed at the touch, left, and screen control preferences at the right – shows that while the center of the screen is the most accessible area, people can easily change the position of their hands to reach any part of the screen.
As you’ve noticed before, users control the central part of the screen most accurately and quickly – and this data is also true with one hand. However, when a person can choose which hand to hold the phone and choose to hold the phone with one hand and control the thumb (as in the figure below at right), the area of use is quite small.
Going beyond this area doesn’t seem particularly difficult – most people simply slow down the speed of use or intercept the smartphone with their other hand, giving the thumb the ability to move around the entire surface.
According to these observations, interaction outside the central area of the screen almost always requires both hands to be involved: either the user presses the device and moves the control arm, or simply holds it in one hand and presses the index finger on the other.
It should be understood that a typical user can easily reach all areas of the screen of any phablet. If he is uncomfortable holding the phone in one way, he will simply change the position of his hands to a more comfortable one.
Three-axis navigation on a flat screen
Essentially, the thumb moves in a wide range – bending and extensor – not from the point where it connects to the rest of the arm, but from the metacarpal joint to the wrist, as shown in Figure 4. In addition, thumb joints, tendons and muscles interact with other fingers, especially the index finger.
The thumb is the strongest, so navigating with it means using weaker fingers to support your phone. The limited range of movements and small force leads to the fact that you need to use the second hand. If the user waits for a meeting or is in the crowd, he prefers to press the device with one hand, holding and protecting it with his finger, which is not used to control.
A recent study by Alexander Ng et al. focuses on what it’s like to try to hold other objects while you’re on the move. In this case, single-handed operation has a particularly negative effect on accuracy.
There is also small-scale research on understanding physiology in the context of touchscreens and models of interaction with them, but it also dates back to earlier times.
There is some doubt that these studies are applicable to contemporary design because they do not correlate well with observed human behaviour. But there is hope that working models will emerge sooner or later, and it will be possible to refer to preferred and effective areas of control for any device and each target group.
People change hands a lot
Don’t forget that these diagrams are for right-handed control, and they do not cover all cases. According to observations, in about 11% of cases the device is used by the fingers of the left hand. It should be noted that this is not a question of right-handed persons, but of those who prefer to carry a smartphone in their right hand.
The assumption that everybody uses the phone with one hand is wrong, even when it comes to wide-screen phones and tablets. In this test, less than half of the participants used only one hand throughout the test, the rest of the participants regularly changed the position of their hands. People use a non-dominant hand and often change one hand to the other, as shown in Figure 5.