I get the same feeling as dublin. Theory: vertical is one-handed, definitely never two. Pushing is therefore weak. And to push it means you're going to increasingly wedge your own hand in between the handle and door as you go. Ouch!
Horizontal: two hands is invited and you know viscerally that you're stronger that way so you don't even consider using one. Pulling this backwards would be strange since you'd have to walk yourself backwards even though you want to go forward. Plus you can't go straight backwards or you'd have to let go with one hand, so you'd have to go at an arc and end up having to run around the door you just pulled out to go through.
I think our bodies understand those things subconsciously in about 300 ms.
Horizontal: two hands is invited and you know viscerally that you're stronger that way so you don't even consider using one. Pulling this backwards would be strange since you'd have to walk yourself backwards even though you want to go forward. Plus you can't go straight backwards or you'd have to let go with one hand, so you'd have to go at an arc and end up having to run around the door you just pulled out to go through.
I think our bodies understand those things subconsciously in about 300 ms.