Baby-brain DVDs don't work because they don't create deep practice—in fact, they actively prevent it, by taking up time that could be used for firing circuits. The images and sounds on the DVDs wash over the babies like a warm bath—entertaining and immersive but useless compared with the rich interactions, errors, and learning that happens when babies are staggering around in the real world. Or, to put it another way: Skill is insulation that wraps neural circuits and grows according to certain signals.
