What has been stated above is very true.
Let me play the devil's advocate here:
Bodybuilder types have been attempting many different methods to get different parts to develop faster than others. Even though spot fat reduction has not been proven, it could be aided by stimulating and emphasizing certain muscles and certain muscle fibers.
CT at T-nation has written a pretty smart article in defense of increasing mass in one part of the body. In theory, if you increase the stimulation by creating a synergistic dominant environment, you should get the effects you want. Of course this method will go against functional and AA type training, but bodybuilders usually care nothing for such things anyway.
So, you could possibly stimulate the middle chest fibers more than other chest fibers by manipulating certain factors in human kinetics.