When you say that a behaviour "makes no difference" you are always mapping that difference against some prior set of expectations. Because every behaviour makes some difference; the question is whether the difference it makes is (a) relevant, and (b) desired. So when I read that "reading to your children makes no difference" I look for the completion of that sentence, which is, "... to educational attainment." Leaving aside what an unpacking of 'educational attainment' would reveal, I look to the possibility of other benefits - the easy association, for example, of text and phonetics, something that would never show up on a written test, but would reward the child with a rich inner life of many voices and nuances. The moral of the story? To Assume that 'educational attainment' is the purpose of learning is to miss most of the value of learning.