In his book The Myth of the First Three Years, the cognitive neuroscience expert Jon Bruer showed that there was no science behind these astonishing claims.41 No psychologist has ever documented a critical period for cognitive or language development that ends at three. And though depriving an animal of stimulation (by sewing an eye shut or keeping it in a barren cage) may hurt its brain growth, there is no evidence that providing extra stimulation (beyond what the organism would encounter in its normal habitat) enhances its brain growth.
Myth of three years
