Studies show that the usage of your mobile phone affects your brain. Further research says daily mobile menu users have a larger and more developed somatosensory cortex; a region that controls our thumbs. Most users use their mobiles with one hand and they either use their right or left thumb to interact with the screen, like a computer mouse but with limitations.
Thumb becomes Mouse
It is easy to navigate on a desktop with the help of a mouse. This is because the mouse does not restrict our wrist movement. But when users switch to mobile interfaces, their thumb has a limited range of motion. There are certain areas of the interface that they cannot reach depending on the phone’s size.
When a menu is placed in a difficult to reach the area, users either have to rearrange their phone so that the thumb will move closer or they have to use their other hand to interact. This is extra work which slows down the user’s task.
Large Screen Vs. Small Screen
As more and more users are opting for large screen phones, the top areas are getting harder to reach than in the case of smaller screen sized phones. The biggest problem with this is that large screens have real less reachability towards the top corner opposite to the thumb.
The Law of Thumb Reachability
A designer, of course, cannot change how users hold their mobile phone, but they can change the placing of the navigation menu. Placing the navigation menu at the top is a convention for desktops but the same doesn’t work for mobile screens as the top is the hardest to reach for the thumb. To make navigation faster, it is thus necessary to place the menu within the thumb’s reach that is the bottom of the screen. That is where your menu should go with a priority hierarchy. The high priority options should be at the lowest within the thumb’s immediate reach and the low priority options towards the top.
The Thumb Sweet Spot
Now the hand that the users will hold to hold their respective phones will vary according to their preference. Which side should you place your menu then? Research has discovered a ‘sweet spot’ which allows users to not stretch their thumbs or bend either to reach the spot. Now you can imagine where the sweet spot is! It is right in the middle of the bottom. That’s the spot which is easiest to reach from the left or right side.
As more and more people are opting for large screens these days, this becomes an important feature as smaller screens don’t have reachability issues. This mechanical efficiency will lead to faster completion of tasks.
Thumb Function Dictates Menu Form
However conventional it seems to place a menu at the top, remember that this placing ignores the user’s thumb functions. Thumb being the primary interaction digit, it should dictate the placing. A hard to use menu decreases navigation speed and customer satisfaction. A UX designer’s goal is to go for the smoothest of design. Remove the obstacle of less reachability with a simple change and enhance the experience you provide henceforth!