The contrast of black and other colors is stimulating to a child's development of eyes and brain. Initially their eyes appreciate the strong contrast. In the first months to a year of life when all of those initial visual and mental synapses in the brain are connecting, clear contrast can be useful. But here is where folks can over do it. Many parents, grandparents, aunties and uncles and other caring adults make everything in a baby's world all bright primary colors. The down side of ALL bright colors is that they can be OVER stimulating. Strike a balance of white/black, soft and strong colors. Consider the colors in our nature. They are not all the same or of the same hue or intensity. Babies like and grow with a dose of all colors particularly when they are accompanied with interactions, smiles and attention from caring adults.
I vote yes, mmunchkins, for using black in juvenile or baby quilts. Our eyes appreciate the spectacular look of a quilt with a splash of black to show off the other colors. A little person would also. Like aashley333, it is just a color.