Then I asked this student play this combination again with his right hand raised and observe his feeling. Afterwards he told us that it was a strange feeling, he felt his attention shift to the raised hand, his tempo was slower, and yet he succeeded with this exercise.
I asked him how he managed to do this and we came to the conclusion that the key here was to really focus on the left hand. It was more difficult of course when he was holding his right hand high in the air but it wasn't impossible.
After him another student (who studies physics) played his own organ arrangements of music from computer games he likes to play. He voluntarily raised one of his hands from time to time as he tried to play his arrangement with just one hand and pedals. Sometimes the right hand and sometimes the left hand was up in the air.
Finally, I told them the story when I was a student at the Lithuanian Academy of Music long time ago and during one of the first lessons, Prof. Leopoldas Digrys, a legendary Lithuanian organist and teacher, asked me to play very independent pedal part of one composition by Bach with both of my hands raised. This way, he explained, no bench and no crutch can help you and you will have no choice but to figure out the way to play the pedals independently.
You too, can try raising one or both hands in the air while you play the rest of the parts and see how you feel.
Sight-reading for today:
Allegretto Grazioso by Alfred Hollins (1865-1942), an English organist, composer and teacher.