They are mono, but I was trying to say that with practice, you can process 2 independent audio streams simultaneously irrespective of whether they are mono or stereo. For example, I am able to keep track of 2 people talking at the same time. I obviously can't respond to both but can maintain independent contexts.
I wonder if piano players find that easier too, compared to lay people.
I do it too, but I "buffer" one person's speech while I process the other's, and vice versa. Do you process both at once?
I think it was wondered whether you were having the independent streams panned hard to the left and right ears and if that had something to do with hemispheres of the brain and the processing efficiency.