Hi grovelli, really good question
You are right that hemispheric brain regions control opposite body areas. So sound focussed into the left ear would have more influence over the right hemisphere of the brain. The right hemisphere has more to do with pattern recognition (such as 'intuition' etc.) so we could conclude that talking to the left side may have more influence over the right hemisphere functions which are more in tune with instinctive pattern recogntion.
However it also of course depends on what is being said not just what side it is said to. For example a logical, sequental list of items read into the left ear wold still appeal to left hemispheric function....and a poem read into the right lobe would still more appeal and more likely be processed by, the right hemisphere. However oppostite 'lobe listening' (My God what have I become-just listen to me-and not with your right lobe
) I guess would make it easier for the brain to function either in pattern or sequence.
So next time you have a phone reciever to your ear think about which ear it up against and what type of conversation you are having.
Mark