Why iPhones have sound control buttons on the left side of the device? We may assume that there are more righthanded users than lefthanded. If user hold the device in right hand, he can use his thumb to perform any actions on a screen (such as unlock phone or lock it - lock button is located at the top right side). But he can't use his thumb to change sound volume. Why it is so?
My guess as to the reasoning is because most right-handed users would hold the phone with their left hand and use their right hand to tap the iPhone (when not using it one handed).
The primary interaction is still happening with the right hand, while they are holding it with their left as seen in the photo below.
**This is all speculation*
Most of the time you would need to change the volume is when you're actually on the phone. Hold your phone to your ear and see how easy it is to change the volume with your index finger.
Because you're gripping the phone using your thumb you would accidentally press the volume buttons if located on the right side.
No one knows for sure why Apple does what it does, but my guess would be that most people are right handed and, as such, interact with the screen primarily via their right hand and, therefore, hold with their left.
When you hold the phone in you right hand, you can use the index finger or middle finger of your right hand for all side and top buttons (volume up, down, flight mode, lock). Alternatively you can use the fingers of your left hand too.
Why would you need/want to adapt volume with your thumb?
