Read this article in The Journal about the impact that different methods of reading instruction have on the brain activity. When decoding new words the left brain is active. If we want children to use the left brain when they read – synthetic phonics is the answer!
http://thejournal.com/articles/2015/07/02/how-phonics-is-taught-can-affect-how-well-a-child-learns-to-read.aspx