I've attempted David Hammill's UX challenge to redesign the iPhone screen for accepting or declining a call while you are already on another one.
These feelings are very relatable. As an iPhone user, when I get a second incoming call, I panic and freeze. Eventually, the caller gives up, and the problem resolves itself.
What causes cognitive overload?
Making decisions for two calls at the same time
Repeating icons that apply to different calls
Labels with two actions are hard to process
All of this while talking to someone or having someone wait for you to solve this puzzle — no pressure!
Separate contexts
When a new person calls, the iPhone prioritizes that call and asks the user to make a decision while they are in the middle of another task. It’s overwhelming for the user.
Here I am, talking to Jim Carrey, and suddenly I see "Margot Robbie" in big letters on my screen. What happened to Jim? Is he still there?
Everything incoming, while the user is in the middle of a task (calls, messages, Taylor Swift ticket sale notification) is just that — a notification.
The main changes:
Keep the user in the context of the current call
The incoming call is a notification that can only be dismissed. The tasks are asynchronous; a new one cannot be initiated until the previous one is completed.
If the user wants to accept the second call, they need to first sort out the current call (End or Hold).
This is my proposed solution. Would be very interesting to test it.