On a doubled ear, the ear would be raised and enlarged, not just an outline next to the ear like Machine Doubling would be where it flattened part of the ear:
Machine Doubling flattens the normal device and people think it is a doubled die. MD is flat looking, and doesn't usually enlarge the devices. Note on the examples below. All the areas that people think are doubled is actually an area flattened after the normal strike reducing the devices by the machine. A doubled die has the doubling on the die. Not caused by the machine.