I paint with both hands at once, creating abstract figurative forms with Asian brushes. (See film) This is not in the Zenga tradition, or any tradition except her own. An invention derived from the necessity of knowing exactly where her brush is on the paper when she is not actually looking at the page at all but at a live model while quickly bringing it to life on the page.
Clap your hands in front of your nose. Now cross your hands and touch your left ear with your right hand and with your left hand touch your nose. Clap again and switch over hands i.e. touch the right ear with your left hand and touch your nose with your right hand. Do this ten times. Rather difficult isn't it?
This movement requires you to use both brain hemispheres simultaneously. From this you can conclude that it is not an automatic response to use both brain hemispheres simultaneously, but a developed or learned response. This demonstration illustrates the value of development.
All people can learn to utilise both brain hemispheres simultaneously, but this will not happen automatically. It can only happen through the right development. Some people use both brain hemispheres, but the dominant brain hemisphere is still preferred and used more than the non-dominant hemisphere. The ideal is for a person to use both brain hemispheres simultaneously and equally.