Visual stimulation provides information as well as critical elements necessary to support neural growth.
When an infant fixates on a pattern, there are changes in his brain wave activity, and there is an increase in the blood flow to the areas of the brain involved in the stimulation.
There are several beneficial consequences to all of this. First of all, patterns are the source of all information for the mind. Hence, this is the beginning of the development of concepts, which is half the battle in language acquisition.
The more patterns the child experiences, the more information the mind will have to work with.
But, equally important is the impact that the stimulation has upon neural growth! We have already noted that neural activity is a major contributor to the neural growth process. More neural activity means more growth. In addition an increase in blood flow to thoswe stimulated areas means a greater supply of oxygen, protiens and other important nutrients for growth.