I can make her change at will. But it started off left-brain. I can switch pretty quickly, always have been able to do so. May have to do with years of Karate training. It has to do with the ability to go into instantaneous relaxation.

The guy who posted that he changed constantly between the two evidently has right and left hemispheres that are working together all the time. That is a characteristic that geniuses usually have. Men have more of a tendency to have right and left brains that can work together while women have less of a chance of having that. That may be while there seem to be more male geniuses than female. That doesn't mean we don't have any; it just means that the male has the better odds. It has to do with brain development.

My sister was a therapist and did a lot of research on the brain. The above info came from one of the "brain" seminars she gave. The brain is endlessly fascinating.